Posts Tagged ‘ALLOW’

Improve MobaXterm Best Windows terminal client with some additional settings tune ups / Install extra Linux Cygwin tools on MobaXterm and various post install configuration goodies

Friday, January 20th, 2023


Earlier I've written a an article MobaXTerm: A good gnome-terminal like tabbed SSH client for Windows / Windows Putty Tabs Alternative in which I've introduced the best in my opinion SSH / Telnet / VNC / RDP / Xserver in one Terminal client emulator for Windows operating systems.

The client has been around for quite some time and it has been improving rapidly over the last 10 years, where it now more looks like a separate Operating System than a single terminal client. It's size is quite compact as well and my opinion and every self respectiving developer, system administrator, IT geek or a hacker would definitely
use the mobaxterm at home or at work place on a daily. I guess some of my readers, who have already migrated SuperPutty / SecureCRT or Putty / XMing or whatever kind of exotic Remote SSH Console terminal is used could validate this 🙂

Therefore as I've set up Mobaxterm on a multiple computers all around, I've found it useful to write a small article with some post-install hints (tune ups) one can do immediately once he has installed the Desktop or Portable Apps version of mobaxterm on desktop PC / notebook.

1. Set up your bashrc server / command aliases

Lets say you need to setup some rules for connectivity via a socks proxy to dig holes over a harsh company firewalls or add
custom options to every ssh client attempt to remote server, or simply alias some of your servers with custom connectivity options
and so on simply open vi / vim text editor from mobaxterm local terminal and place inside your rules, for example that could be anything like:


alias ssh='ssh -o stricthostkeychecking=no -o passwordauthentication=yes -o PreferredAuthentications=password  -v'
alias sftp='sftp -o stricthostkeychecking=no -o passwordauthentication=yes -o PreferredAuthentications=password'

alias work-server='ssh UserName@work-server -v -o passwordauthentication=yes -o PreferredAuthentications=password'

alias proxy='ssh -D 3128 UserName@proxyIP-host1 -o ConnectTimeout=80'
alias proxy1='ssh -D 3128 UserName@proxy-host2 -p 443 -o ConnectTimeout=60'
alias proxy3='ssh -D 3128 Username@proxy-host3 -p 443 -o ConnectTimeout=60'

Simply open the terminal and setup whatever you require
export ftp_proxy="http://proxy-host:8080"
export https_proxy="https://proxy-host:8080"
export http_proxy="http://proxy-host:8080"
export HTTP_PROXY="http://proxy-host:8080"
export HTTPS_PROXY="http://proxy-host:8080"


2. Set mobaxterm presistent directory / persistent root directory and default text editor

Make sure you have properly defined at least Persistent directory / Persistent directory if you want to keep the files under your /home/mobaxterm and root directory be able to save your data from local mobaxterm terminal work you have done.

To do so o to Configuration -> General


3. Change default settings for Opening / Closing Terminal tabs just like in gnome-terminal

MobaXterm is really awesome as the developer, followed pretty much the logic of some common GNU / Linux Terminal clients like Gnome-Terminal and KDE's default Konsole terminal.

One of the first things to do once Mobaxterm is installed on the PC is to set up nice key binds as default onces might be heard to learn at the beginning or you might have already the habit to use the certain set of key combinations on your Linux desktop:

Common once are:

1. Open tab / Close tab common once I bind to are (CTRL + T / CTRL + W)
2. Previous tab move / Next tab move keys common one I use are (ALT + LEFT / ALT + RIGHT)
3. Find in terminal (CTRL + F)


4. Make MobaXterm to automatically open a terminal to not Start local terminal every time

By default mobaxterm it is really annoying cause every time you run it after system reboot you have to select
Start local terminal
Once you run the terminal you get this prompt and you have to press on Start local terminal


How to make Mobaxterm automatically open local Terminal Tab on every boot?

To fix this so every time a local terminal is spawn on MobaXterm you have get to:

Settings -> Configuration -> Misc

Open the Following tab at startup by default it will be

<Home (Pinned)>

Change it to:



That's it on next login your Local Terminal with /bin/bash.exe will auto load !

[hipo.WINDOWS-PC] ➤ env|grep -i SHELL

5. Make menu buttons to appear smaller

Go to menu and select
View -> (Small Buttons)


6. Disable auto start of XServer to prevent a port listener on the machine on TCP port

By default mobaxterm opens XServer listener, so you can immediately connect from a remote SSH servers missing Xserver and install software requiring an XServer, for example software such as Oracle Database or some MiddleWare WebLogig or IBM's Web Sphere. This is useful but if you want to have a good security only allow this server on a purpose. Otherwise the XServer will run in parallel with rest of your Moba and just load up your PC and eat up some RAM memory. To disable it go to:


7. Change the mobaxterm Default theme to Dark

This is optional I like to set the Theme to Dark, also as a Theme for Windows as well as for MobaxTerm, the aim of that is simply to not put extra stress on my eye sight. Being on the PC around 8 to 10 hours and spending some 6 to 8 hours on console work is enough. If you want to do as well.


8. Install additional set of common Linux tools to mobaxterm to use on Windows

Tools such as:

1. Midnight Commander (mc)
2. Wget
3. Curl
4. Vim
5. Screen
6. Rsync
7. Perl
8. W3m
9. dosunix
10. unix2dos
11. gnupg
12. diffutils
13. mysql
14. mpg123
15. whois

If you want to have a set of packages pre-installed that are including above as well as the rest of mine, here is a dump of my installed mobapt manager packages:

For more simply use the experimental Mobaxterm  Graphical Package installer

[hipo.WINDOWS-PC] ➤  for i in $(cat Downloads/installed-packages-mobaxterm.txt ); do apt-cyg install $i; done

Found package GeoIP-database

Installing GeoIP-database
Downloading GeoIP-database-20180505-1.tar.xz…
Unpacking GeoIP-database-20180505-1.tar.xz…

Running postinstall scripts
Package GeoIP-database installed.

Rebasing new libraries

Found package adwaita-icon-theme

Installing adwaita-icon-theme
Downloading adwaita-icon-theme-3.26.1-1.tar.xz…

You will be prompted for a single Yes for the respository

MobApt Packages Manager


Though it is said it is experimental, I have to say the MobApt Apt Manager works quite good, I never had any issues with it so far.

9. Mobaxterm.ini the settings storage file that can help you move your configurations

If you have to prepeare new MobaXterm on multiple PCs frequently perhaps it is best to just copy the Mobaxterm.ini file. 
Here is an example of my mobaxterm.ini for download.

10. Change terminal colors and curor type and enable blinking (customizations)

Settings -> Configuration -> Terminal -> (Default Terminal Color Settings)


11. Use very useful moba Tools

For sysadmins Moba has plenty of other jems such as:

  • Network Port scanner such as Nmap with GUI

  • list open network ports (GUI interface to netmap)

  • SSH tunnel tool

  • Moba Diff

  • Wake on Lan

  • Network Packet capturer (such as tcpdump)

  • List running processes (such as taskmgr in simple form)

  • List machine hardware devices (such as Windows Device manager)

12. Remote monitoring of opened ssh session

To enable remote monitoring for a Saved session simply use the "Remote monitoring" button on the down left corner of the terminal.


Or to enable it for a new host, open:

1. "Saved sessions"
2. Click over "User sessions"
3. New Session -> (SSH)
4. Basic SSH Settings (Remote host) -> OK
5. Click over the new created session
6. Click on Remote monitoring for the opened session


13. Play some mobaxterm console games

As you might have pissed off of configuring go on and enjoy some of the great console games, some of which are also present on a normal Linux new distribution installation. 🙂


List of Moba Games

TeamWalk (Use your mouse or keyboard to connect every server to the central router)


Ctris Console tetris from Mobaxterm


Text console Solitaire from Moba


Here is NinVaders (Text Version of Space Invaders Arcade Classic)

Enjoy ! 🙂

Saint Filothea Temnishka of Tarnovo feast day 7 of December. A XII century miracle working Saint little known in the West

Tuesday, December 14th, 2021


Living of Saint Filothea of Tarnovo 

The Venerable Filothea (Filotea) is born in the Byzantine city of Polivot in (Southern Thrace). She was a fruit of a continous prayers of her parents. 
Received a good education for the time and reached adulthood, her parents give her for a bride (in arranged marriage against her will) which was a standard practice of its time.
Even merrying using  her enormous wisdom she was able to persuade her husband to live vestal life (the marriage was not consumed). 
In relatively short years her husband passed away. She has moved to a Insland nearby the close lake, built a small hermit cell hut and prayed and fasted incessantly living a a holy hermit life in solitude, night vigils, tears and repentance and stillness.
Because of her zealoutry God has given her the Grace of Miracle working prayers and the wisdom to teach. A well known spiritual persons, cleargyman, priests, deacons and people come to her to hear her graceful words and councils as well as to receive a healing through her holy prayers.


Cause of her absitence of food and sleep and praers all over the clock she lost body weight, forseeing her death she has presented herself to the Lord on 7th of December (the exact year of her death and the age are unknown, presumably she lived somewhere in the XII century). Her holy relics turned to be incorruptable (a sign for immerse holiness, among with wonder working healing miracles were considered some of the conditions for considering a deceased person a saint – for more on inccorruptability of saint relics check out my previous article here).


In the beginning of XIII century her holy relics were solemnly carried with honor from Polivot to the Capital of Second Bulgarian Empire Tarnovo by King Kaloyan. There her holy relics stayed by God's great providence for 200 years, being visited by the whole Christiandome for veneration.


After the fall of Bulgaria under the Ottoman yoke (year 1393). Probably to save the holy relics from destruction, they were taken to the far North Bulgarian borders in the Fortress of Bdin (today city of Vidin) and after staying for a while once the fortress was taken over by Mohameddans, taken a by the Serbs, and later Wallachs (todays Romanians) has taken the relics from Serbs, once the Serbian lands were invaded.

Currently her holy relics are present the old Wallachian Capital Curtea de Argeș (near river of Argeș).

Holy Relics of Saint Filothea, one of the most famous places for Christian veneration in Romania
(Saint Demetrius of Besarabia – another Bulgarian saint, Saint Filotea, and Saint Petka of Bulgaria are among the most venerated saints in Romania today)

The main source we have for the living of Saint Filothea (Filotheus) is written by Saint Patriarch Euthymius of Tarnovo Bulgaria (born circa 1325, died c.1402 / 1404). It is a very long document describing a lot of interesting details about Saint Filothea's healing miracles after she prayed with crying to the Lord even before she died. The miracle healings, chasing out of demons and restoration of eye sight and other glorious things continued even after she passed out to Christ to multitudes of people who prayed in front of her relics with faith.

Saint Patriarch Euthymiuus of Tarnovo, the main source author for today's Filoteas Living 

During her life she spoke to the people coming to her a lot of his sacred methodical words.
She told them before her death:

"The time has come for me to leave here, so I thought it right to remind you of the traditions and decisions of the Orthodox faith by the Holy Apostles and the Divine Fathers. You know that the Orthodox faith is the head of our lives. In your efforts to give it to us pure and immaculate, the Holy Apostles suffered various kinds of death. , and to keep the church traditions unshakable, and not to waver here and there from different winds.

However, the Lord Jesus Christ shed His blood for her and did not allow his Church to be completely destroyed. But he gave her help, and fate led her to victory. I, the poor, have been brought up in piety since my childhood, and I received it from my parents as a precious treasure. Therefore, as a holy peak in the Church, I ask you not to forget the tradition of the Holy Prophets and Apostles, as the great apostle Paul wrote to Timothy: and others to learn! " (Tim. 2: 2)


You deserve to hold the true faith and not listen to pagan fables at all. They can rebuke us a thousand times, they can insult us a thousand times, but a lie will never defeat the truth, nor will malice prevail over wisdom. For, they reduced the name of the Deity in the creation, in men – oh wickedness! – in trees, in stones, cats, dogs, and are not ashamed to think that creation came into being by itself, and do not understand, the unthinking, in their evil wickedness and wisdom, that everything was brought from non-being into existence by one true God, Who created heaven and earth and everything visible and invisible. And the gods, who did not create the heavens and the earth, may perish! (Jeremiah 10:11). Let those who make them and who hope in them be like them! (Ps. 113:16; 134:18). Therefore the Gentiles were deceived, and their foolish hearts were darkened. Considering themselves to be wise, they proved foolish, and changed the glory of one God in the likeness of quadrupeds, reptiles, and birds (Rom. 1: 21-23). Let the wretched see where the celestial bodies and earthly beings in the air and water came from, and most of all where the even more primitive came from – heaven and earth, air and aquatic nature! Who mixed and divided them? What is their communication with each other – separation and consent? Who moves and leads them? How does one element, which is contrary in nature, run away with another harmlessly in the fullness of one world? How do they exist in agreement without consulting and talking? All this is the work of divine providence, and they left the Creator and honored and served creation instead of the Creator (Rom. 1:25) and wander in vain and rage against our pious faith and against pious Christians, to whom they impose ruthless torture and force them to renounce the sweet name of Christ.

You do not pay attention to their threats, even if they lead you to the torturous wheels, to the boiling cauldrons, to the sword or fire, do not be afraid of their horrors! (Isa. 8:12, 70s). Another life and another age that awaits us awaits us, where the prophets rejoice, the apostles rejoice together with the figures of the Venerable Lent, with the angels and archangels, with the martyrs and all the saints. Always think this, write this in your hearts! Take care of yourself and the whole flock, among which God has appointed you shepherds and teachers (Acts 20:28), in order to keep yourself and them pure and undefiled!

Everything in this world will be beautifully and habitually scattered like dust and forgotten, only virtue lasts forever and ever. Therefore, try to keep yourself clean and to lead the entrusted flock to lively pastures, so that the Lord of all, seeing this diligence of yours, may reward you with a reward worthy of your labors and make you worthy of His kingdom! " 

Romanian Contemporary Icon of Saint Filothea

A high-ranking and famous man named Navkratius, from the city of Amoria, was appointed by the then king to be the governor of Greece. It happened to him to fight the godless Agarians (The Turks), and after the two sides fought, by the unknown destinies of God, his whole army was defeated: some were killed, and others were captured and taken to Sicily. Along with the others, a stratilat (army commanded) was captured, but his name was Artavan, from the town of Philomelia. Taken away by the ungodly, they were imprisoned in a gloomy dungeon and guarded with great care. Thus detained there, they were perplexed as to what to invent and what to do. And overwhelmed with grief, they called for the help of Almighty God and His loved ones.

Then Artavan remembered St. Philothea and began to tell them about her glorious miracles and that she had received the gift of healing various ailments and diseases. As he listened to Stratilat Navkratius, his heart burned and he began to call for her help. And because he was filled with divine desire and was inflamed with fervent faith, he could not wait to hide it for a long time, but he quickly got up and raised everyone to earnest prayer, shedding tears. And all of them unanimously rushed to earnest prayer and called for the help of the God-loving Philotheus, saying:

"Christ-related slave, undefiled bride, pure dove, abode of the Holy Spirit, if you look mercifully on us humble and desperate, and free us from this terrible dungeon, we will be trumpets of your countless miracles, with a loud voice we will we preach, and we will spend the rest of our lives chaste and pure. O Venerable Mother, do not despise us, for we are bitterly distressed in this terrible and miserable dungeon! "


With such prayers they spent the whole night, with hot tears and heartache. When they had finished this all-night vigil and finished their prayer, they lay down to rest and give a little sleepy consolation to the body. Everyone fell asleep in their place, the reverend appeared to them and rejoiced their hearts with words of consolation, saying:

"Your prayer has been heard and God has not despised your sighs. So go in peace and return to your homes, thanking God for your gratitude, who frees prisoners from bondage!" (Ps. 67: 7).

They awoke with joy, the iron chains lay fallen from them, the dungeon was wide open. They believed the vision to be true, and immediately left the open dungeon, the guard lying as if dead, and fleeing freely. But before they went home, they first went to the island to pay their respects to the reverend. After fulfilling this obligation, each of them returned home and told all the glorious miracles of the Venerable Philoteia.

After this spread everywhere, and managed to enter every ear, a leper, full of faith and fervent zeal, quickly came to the church of the Venerable Mother, called for mercy and with diligent requests and frequent bows, long sleepless nights, fasting and torture tormented himself and he relentlessly spent in her divine temple. The Blessed One, seeing his long diligence and his bodily leprosy, which had almost ended, immediately bowed to mercy, appeared in the dream of the church cleric and ordered him to anoint him with oil from the holy chandel of the Immaculate Conception all over his body. When he awoke, the cleric quickly obeyed the order. and not many days later he sent him safe to his home to glorify and thank God, as well as to His close friend.

A lot of time passed and many miracles happened. The Greek kingdom was exhausted and its scepter holders found themselves in difficult circumstances. Finding the right time, the Romans stormed the Greek state and inflicted unbearable misery.

At the same time, the Bulgarian kingdom became very strong and powerful, and it encompassed and conquered all the surrounding areas. At that time in Bulgaria the tsarist scepter was ruled well and even magnificently by the pious and glorious tsar Kaloyan (1197-1207). Seeing the Greek kingdom completely exhausted, he attacked it manfully, and many cities and villages were captured and ruined. And having gathered all the good, he brought it to his glorious city of Tarnovo – the whole nation with all the animals moved to their country. As he did all this, he heard the miracles of the Venerable Philotheus, and his heart was greatly inflamed. Because it is usually a matter of the souls of the pious to show zeal for virtue and to show zeal in every way.

After conquering the whole region and subduing it to his authority, he came to the place where the venerable body of the reverend lay, filled himself with unspeakable joy, praising God and diligently thanking Him. He fell before the reverend relics of the reverend, flooded them with his tears, and reverently kissed them. He then ordered an all-night vigil and gave many alms to the poor. In the morning a divine liturgy was celebrated, which was attended by the king in great joy and merriment with all his army. And he made the good decision to bring the reverend's body to his country. 

Holy Venerable Mother Filothea pray the Lord to have mercy on every suffering and needy, poor, sick, weak and low and all the people who remember your holy memory and summon your prayers !

Amen !

Article Sources:
1. The Living of Saints by dr. Atanasii Bonchev and bishop Partenij 
2. The Living of Saint Filothea written by Saint Patriarch Euthymius of Tarnovo


Adding custom user based host IP aliases load custom prepared /etc/hosts from non root user on Linux – Script to allow define IPs that doesn’t have DNS records to user preferred hostname

Wednesday, April 14th, 2021


Say you have access to a remote Linux / UNIX / BSD server, i.e. a jump host and you have to remotely access via ssh a bunch of other servers
who have existing IP addresses but the DNS resolver recognized hostnames from /etc/resolv.conf are long and hard to remember by the jump host in /etc/resolv.conf and you do not have a way to include a new alias to /etc/hosts because you don't have superuser admin previleges on the hop station.
To make your life easier you would hence want to add a simplistic host alias to be able to easily do telnet, ssh, curl to some aliased name like s1, s2, s3 … etc.

The question comes then, how can you define the IPs to be resolvable by easily rememberable by using a custom User specific /etc/hosts like definition file? 

Expanding /etc/hosts predefined host resolvable records is pretty simple as most as most UNIX / Linux has the HOSTALIASES environment variable
Hostaliases uses the common technique for translating host names into IP addresses using either getaddrinfo(3) or the obsolete gethostbyname(3). As mentioned in hostname(7), you can set the HOSTALIASES environment variable to point to an alias file, and you've got per-user aliases

create ~/.hosts file

linux:~# vim ~/.hosts

with some content like:


linux:~# export HOSTALIASES=$PWD/.hosts

The caveat of hostaliases you should know is this will only works for resolvable IP hostnames.
So if you want to be able to access unresolvable hostnames.
You can use a normal alias for the hostname you want in ~/.bashrc with records like:

alias server-hostname="ssh username@ -v -o stricthostkeychecking=no -o passwordauthentication=yes -o UserKnownHostsFile=/dev/null"
alias server-hostname1="ssh username@ -v -o stricthostkeychecking=no -o passwordauthentication=yes -o UserKnownHostsFile=/dev/null"
alias server-hostname2="ssh username@ -v -o stricthostkeychecking=no -o passwordauthentication=yes -o UserKnownHostsFile=/dev/null"

then to access server-hostname1 simply type it in terminal.

The more elegant solution is to use a bash script like below:

# include below code to your ~/.bashrc
function resolve {
        if [[ -f “$hostfile” ]]; then
                for arg in $(seq 1 $#); do
                        if [[ “${!arg:0:1}” != “-” ]]; then
                                ip=$(sed -n -e "/^\s*\(\#.*\|\)$/d" -e "/\<${!arg}\>/{s;^\s*\(\S*\)\s*.*$;\1;p;q}" "$hostfile")
                                if [[ -n “$ip” ]]; then
                                        command "${FUNCNAME[1]}" "${@:1:$(($arg-1))}" "$ip" "${@:$(($arg+1)):$#}"
        command "${FUNCNAME[1]}" "$@"

function ping {
        resolve "$@"

function traceroute {
        resolve "$@"

function ssh {
        resolve "$@"

function telnet {
        resolve "$@"

function curl {
        resolve "$@"

function wget {
        resolve "$@"


Now after reloading bash login session $HOME/.bashrc with:

linux:~# source ~/.bashrc

ssh / curl / wget / telnet / traceroute and ping will be possible to the defined ~/.hosts IP addresses just like if it have been defined global wide on System in /etc/hosts.


Scanning ports with netcat “nc” command on Linux and UNIX / Checking for firewall filtering between source and destination with nc

Friday, September 6th, 2019


Netcat ( nc ) is one of that tools, that is well known in the hacker (script kiddie) communities, but little underestimated in the sysadmin world, due to the fact nmap (network mapper) – the network exploratoin and security auditing tool has become like the standard penetration testing TCP / UDP port tool

nc is feature-rich network debugging and investigation tool with tons of built-in capabilities for reading from and writing to network connections using TCP or UDP.

Its Plethora of features includes port listening, port scanning & Transferring files due to which it is often used by Hackers and PenTesters as Backdoor. Netcat was written by a guy we know as the Hobbit <>.

For a start-up and middle sized companies if nmap is missing on server usually it is okay to install it without risking to open a huge security hole, however in Corporate world, due to security policies often nmap is not found on the servers but netcat (nc) is present on the servers so you have to learn, if you haven't so to use netcat for the usual IP range port scans, if you're so used to nmap.

There are different implementations of Netcat, whether historically netcat was UNIX (BSD) program with a latest release of March 1996. The Linux version of NC is GNU Netcat (official source here) and is POSIX compatible. The other netcat in Free Software OS-es is OpenBSD's netcat whose ported version is also used in FreeBSD. Mac OS X also comes with default prebundled netcat on its Mac OS X from OS X version (10.13) onwards, on older OS X-es it is installable via MacPorts package repo, even FreeDOS has a port of it called NTOOL.

The (Swiss Army Knife of Embedded Linux) busybox includes a default leightweight version of netcat and Solaris has the OpenBSD netcat version bundled.

A cryptography enabled version fork exists that supports that supports integrated transport encryption capabilities called Cryptcat.

The Nmap suite also has included rewritten version of GNU Netcat named Ncat, featuring new possibilities such as "Connection Brokering", TCP/UDP Redirection, SOCKS4 client and server support, ability to "Chain" Ncat processes, HTTP CONNECT proxying (and proxy chaining), SSL connect/listen support and IP address/connection filtering. Just like Nmap, Ncat is cross-platform.

In this small article I'll very briefly explain on basic netcat – known as the TCP Army knife tool port scanning for an IP range of UDP / TCP ports.


1. Scanning for TCP opened / filtered ports remote Linux / Windows server


Everyone knows scanning of a port is possible with a simple telnet request towards the host, e.g.:



The most basic netcat use that does the same is achiavable with:


220 jeremiah ESMTP Exim 4.92 Thu, 05 Sep 2019 20:39:41 +0300

Beside scanning the remote port, using netcat interactively as pointing in above example, if connecting to HTTP Web services, you can request remote side to return a webpage by sending a false referer, source host and headers, this is also easy doable with curl / wget and lynx but doing it with netcat just like with telnet could be fun, here is for example how to request an INDEX page with spoofed HTTP headers.

nc Web-Host.COM 25
GET / HTTP/1.1
User-Agent: my-spoofed-browser


2. Performing a standard HTTP request with netcat


To do so just pype the content with a standard bash integrated printf function with the included end of line (the unix one is \n but to be OS independent it is better to use r\n  – the end of line complition character for Windows.


printf "GET /index.html HTTP/1.0\r\nHost:\r\n\r\n" | nc 80


3. Scanning a range of opened / filtered UDP ports


To scan for lets say opened remote system services on the very common important ports opened from UDP port 25 till, 1195 – more specifically for:

  • UDP Bind Port 53
  • Time protocol Port (37)
  • TFTP (69)
  • Kerberos (88)
  • NTP 123
  • Netbios (137,138,139)
  • SNMP (161)
  • LDAP 389
  • Microsoft-DS (Samba 445)
  • Route BGP (52)
  • LDAPS (639)
  • openvpn (1194)


nc -vzu 25 1195


UDP tests will show opened, if no some kind of firewall blocking, the -z flag is given to scan only for remote listening daemons without sending any data to them.


4. Port Scanning TCP listening ports with Netcat


As prior said using netcat to scan for remote opened HTTP Web Server on port 80 an FTP on Port 23 or a Socks Proxy or MySQL Database on 3306 / PostgreSQL DB on TCP 5432 is very rare case scenario.

Below is example to scan a Local network situated IP for TCP open ports from port 1 till 7000.


# nc -v -n -z -w 5 1-7000

           nc: connect to 80 (tcp) failed: Connection refused
           nc: connect to 20 (tcp) failed: Connection refused
           Connection to port [tcp/ssh] succeeded!
           nc: connect to 23 (tcp) failed: Connection refused


Be informed that scanning with netcat is much more slower, than nmap, so specifying smaller range of ports is always a good idea to reduce annoying waiting …

The -w flag is used to set a timeout to remote connection, usually on a local network situated machines the timeout could be low -w 1 but for machines across different Data Centers (let say one in Berlin and one in Seattle), use as a minimum -w 5.

If you expect remote service to be responsive (as it should always be), it is a nice idea to use netcat with a low timeout (-w) value of 1 below is example:

netcat -v -z -n -w 1 scanned-hosts 1-1023


5. Port scanning range of IP addresses with netcat

If you have used Nmap you know scanning for a network range is as simple as running something like nmap -sP -P0 192.168.0.* (to scan from IP range 1-255 map -sP -P0 (to scan from local IPs ending in 1-150) or giving the network mask of the scanned network, e.g. nmap -sF – for more examples please check my previous article Checking port security on Linux with nmap (examples).

But what if nmap is not there and want to check a bunch 10 Splunk servers (software for searching, monitoring, and analyzing machine-generated big data, via a Web-style interface.), with netcat to find, whether the default Splunk connection port 9997 is opened or not:


for i in `seq 1 10`; do nc -z -w 5 -vv splunk0$ 9997; done


6. Checking whether UDP port traffic is allowed to destination server


Assuring you have access on Source traffic (service) Host A  and Host B (remote destination server where a daemon will be set-upped to listen on UDP port and no firewall in the middle Network router or no traffic control and filtering software HUB is preventing the sent UDP proto traffic, lets say an ntpd will be running on its standard 123 port there is done so:

– On host B (the remote machine which will be running ntpd and should be listening on port 123), run netcat to listen for connections


# nc -l -u -p 123
Listening on [] (family 2, port 123)

Make sure there is no ntpd service actively running on the server, if so stop it with /etc/init.d/ntpd stop
and run above command. The command should run as superuser as UDP port 123 is from the so called low ports from 1-1024 and binding services on such requires root privileges.

– On Host A (UDP traffic send host


nc -uv remote-server-host 123



If the remote port is not reachable due to some kind of network filtering, you will get "connection refused".
An important note to make is on some newer Linux distributions netcat might be silently trying to connect by default using IPV6, bringing false positives of filtered ports due to that. Thus it is generally a good idea, to make sure you're connecting to IPV6


$ nc -uv -4 remote-server-host 123


Another note to make here is netcat's UDP connection takes 2-3 seconds, so make sure you wait at least 4-8 seconds for a very distant located hosts that are accessed over a multitude of routers.

7. Checking whether TCP port traffic allowed to DST remote server

To listen for TCP connections on a specified location (external Internet IP or hostname), it is analogous to listening for UDP connections.

Here is for example how to bind and listen for TCP connections on all available Interface IPs (localhost, eth0, eth1, eth2 etc.)

nc -lv 12345


Then on client host test the connection with


nc -vv 12345
Connection to 12345 port [tcp/*] succeeded!


8. Proxying traffic with netcat

Another famous hackers use of Netcat is its proxying possibility, to proxy anything towards a third party application with UNIX so any content returned be printed out on the listening nc spawned daemon like process.
For example one application is traffic SMTP (Mail traffic) with netcat, below is example of how to proxy traffic from Host B -> Host C (in that case the yandex current mail server

linux-srv:~# nc -l 12543 | nc 25

Now go to Host A or any host that has TCP/IP protocol access to port 12543 on proxy-host Host B (linux-srv) and connect to it on 12543 with another netcat or telnet.

to make netcat keep connecting to MX (Mail Exchange) server you can run it in a small never ending bash shell while loop, like so:


linux-srv:~# while :; do nc -l 12543 | nc 25; done

 Below are screenshots of a connection handshake between Host B (linux-srv) proxy host and Host A (the end client connecting) and Host C (



Host B netcat as a (Proxy)

that is possible in combination of UNIX and named pipes (for more on Named pipes check my previous article simple linux logging with named pipes), here is how to run a single netcat version to proxy any traffic in a similar way as the good old tinyproxy.

On Proxy host create the pipe and pass the incoming traffic towards and write back any output received back in the named pipe.

# mkfifo backpipe
# nc -l 8080 0<backpipe | nc 80 1>backpipe

Other useful netcat proxy set-up is to simulate a network connectivity failures.

For instance, if server:port on TCP 1080 is the normal host application would connect to, you can to set up a forward proxy from port 2080 with

    nc -L server:1080 2080

then set-up and run the application to connect to localhost:2080 (nc proxy port)

    /path/to/application_bin –server=localhost –port=2080

Now application is connected to localhost:2080, which is forwarded to server:1080 through netcat. To simulate a network connectivity failure, just kill the netcat proxy and check the logs of application_bin.

Using netcat as a bind shell (make any local program / process listen and deliver via nc)


netcat can be used to make any local program that can receive input and send output to a server, this use is perhaps little known by the junior sysadmin, but a favourite use of l337 h4x0rs who use it to spawn shells on remote servers or to make connect back shell. The option to do so is -e

-e – option spawns the executable with its input and output redirected via network socket.

One of the most famous use of binding a local OS program to listen and receive / send content is by
making netcat as a bind server for local /bin/bash shell.

Here is how

nc -l -p 4321 -e /bin/sh

If necessery specify the bind hostname after -l. Then from any client connect to 4321 (and if it is opened) you will gain a shell with the user with which above netcat command was run. Note that many modern distribution versions such as Debian / Fedora / SuSE Linux's netcat binary is compiled without the -e option (this works only when compiled with -DGAPING_SECURITY_HOLE), removal in this distros is because option is potentially opening a security hole on the system.

If you're interested further on few of the methods how modern hackers bind new backdoor shell or connect back shell, check out Spawning real tty shells article.


For more complex things you might want to check also socat (SOcket CAT) – multipurpose relay for bidirectional data transfer under Linux.
socat is a great Linux Linux / UNIX TCP port forwarder tool similar holding the same spirit and functionality of netcat plus many, many more.

On some of the many other UNIX operating systems that are lacking netcat or nc / netcat commands can't be invoked a similar utilitiesthat should be checked for and used instead are:

ncat, pnetcat, socat, sock, socket, sbd

To use nmap's ncat to spawn a shell for example that allows up to 3 connections and listens for connects only from network on port 8081:

ncat –exec "/bin/bash" –max-conns 3 –allow -l 8081 –keep-open


9. Copying files over network with netcat

Another good hack often used by hackers to copy files between 2 servers Server1 and Server2 who doesn't have any kind of FTP / SCP / SFTP / SSH / SVN / GIT or any kind of Web copy support service – i.e. servers only used as a Database systems that are behind a paranoid sysadmin firewall is copying files between two servers with netcat.

On Server2 (the Machine on which you want to store the file)

nc -lp 2323 > files-archive-to-copy.tar.gz

On server1 (the Machine from where file is copied) run:

nc -w 5 2323 < files-archive-to-copy.tar.gz


Note that the downside of such transfers with netcat is data transferred is unencrypted so any one with even a simple network sniffer or packet analyzier such as iptraf or tcpdump could capture the file, so make sure the file doesn't contain sensitive data such as passwords.

Copying partition images like that is perhaps best way to get disk images from a big server onto a NAS (when you can't plug the NAS into the server).

10. Copying piped archived directory files with netcat


On computer A:

export ARIBTRARY_PORT=3232
nc -l $ARBITRARY_PORT | tar vzxf –

On Computer B:

tar vzcf – files_or_directories | nc computer_a $ARBITRARY_PORT


11. Creating a one page webserver with netcat and ncat

As netcat could listen to port and print content of a file, it can be set-up with a bit of bash shell scripting to serve
as a one page webserver, or even combined with some perl scripting and bash to create a multi-serve page webserver if needed.

To make netact serve a page to any connected client run in a screen / tmux session following code:


while true; do nc -l -p 80 -q 1 < somepage.html; done


Another interesting fun example if you have installed ncat (is a small web server that connects current time on server on connect).

ncat -lkp 8080 –sh-exec 'echo -ne "HTTP/1.0 200 OK\r\n\r\nThe date is "; date;'


12. Cloning Hard disk partitions with netcat

rsync is a common tool used to clone hard disk partitions over network. However if rsync is not installed on a server and netcat is there you can use it instead, lets say we want to clone /dev/sdb
from Server1 to Server2 assuming (Server1 has a configured working Local or Internet connection).


On Server2 run:

nc -l -p 4321 | dd of=/dev/sdb


Following on Server2 to start the Partition / HDD cloning process run


dd if=/dev/sdb | nc 4321


Where is the IP address listen configured on Server2 (in case you don't know it, check the listening IP to access with /sbin/ifconfig).

Next you have to wait for some short or long time depending on the partiiton or Hard drive, number of files / directories and allocated disk / partition size.

To clone /dev/sda (a main partiiton) from Server1 to Server2 first requirement is that it is not mounted, thus to have it unmounted on a system assuming you have physical access to the host, you can boot some LiveCD Linux distribution such as Knoppix Live CD on Server1, manually set-up networking with ifconfig or grab an IP via DHCP from the central DHCP server and repeat above example.

Happy netcating 🙂

How to install KVM Kernel-based Virtual Machine Virtualization on Linux

Sunday, October 14th, 2018


If you want to run multiple virtual machines on GNU / Linux server or your Linux powered Desktop you have the possibility to use a couple of Virtual Machines just to name a few VirtualBox and VMWare are the option the native way to do it is using the Linux kernel via a loadable kernel module called KVM (Kernel-based Virtual Machine).
Though Oracle's Virtualbox generally works and you could add new test beds virtual machines (install multiple Linux / *BSD OS) it is not fully Free Software and not even fully open source licensed, VMWare even though superior as a Virtualization product is proprietary and its application costs a lot of money which not each develpoper or small / mid-sized company could afford.

Once the kvm.ko module is loaded your Linux kernel turns into a full-featured Virtual Machine Hypervisor.
Starting with Linux kernel 2.6.X the KVM Hypervisor is available and easy to install virtually all modern Linux distributions Redhat / CentOS Debian / Ubuntu etc. support it and its up to running few commands to install and start using the Power of Kernel embedded Virtualization.

KVM could be used to run in parallel multiple Operating Systems such as Windows / Linux / FreeBSD and others of BSDs family,  each running under a separate virtual machine with its private dedicated (isolated), disc, graphic card, network card etc.

To start up I assume you have already installed some kind of Linux distribution either locally or on a remote dedicated server.

1. Installing KVM on Debian GNU / Linux / Ubuntu / Mint and other deb based distros


Using APT tool install below packages:


root@jeremiah:~# apt install –yes qemu-kvm libvirt-clients libvirt-daemon-system bridge-utils libguestfs-tools genisoimage virtinst libosinfo-bin


2. Installing virt-manager GUI to manage Virtual servers


root@jeremiah:~# apt-cache show virt-manager|grep -i desc -A 1
Description-en: desktop application for managing virtual machines
 It presents a summary view of running domains and their live performance &

Description-md5: 9f7f584744b77cdacc2291f2a8ac220e


root@jeremiah:~# apt install –yes virt-manager






3. Configure bridged networking to allow access to newly configured VMs

Bridging has to be added via /etc/network/interfaces therefore it is a good idea to create a backup of it before modifying:


# cp -rpf /etc/network/interfaces /etc/network/interfaces.bakup-$(echo $(date '+%Y-%m-%d-%H'))


# vim /etc/network/interfaces

auto br0
 iface br0 inet static
         # set static route for LAN
      post-up route add -net netmask gw
      post-up route add -net netmask gw
         bridge_ports eth0
         bridge_stp off
         bridge_fd 0
         bridge_maxwait 0
 # br1 setup with static wan IPv4 with ISP router as a default gateway
 auto br1
 iface br1 inet static
         bridge_ports eth1
         bridge_stp off
         bridge_fd 0
         bridge_maxwait 0


Once file is saved in vim editor restart the networking.


# systemctl restart network.manager


To verify whether the bridge has been succesfully upped.


root@jeremiah:/home/hipo/kvm# brctl show
bridge name    bridge id        STP enabled    interfaces
virbr0        8000.525400cb1cd1    yes        virbr0-nic


4. List all installable Virtual OS images

root@jeremiah:/home/hipo/kvm# virt-builder -list
centos-6                 x86_64     CentOS 6.6
centos-7.0               x86_64     CentOS 7.0
centos-7.1               x86_64     CentOS 7.1
centos-7.2               aarch64    CentOS 7.2 (aarch64)
centos-7.2               x86_64     CentOS 7.2
centos-7.3               x86_64     CentOS 7.3
centos-7.4               x86_64     CentOS 7.4
centos-7.5               x86_64     CentOS 7.5
cirros-0.3.1             x86_64     CirrOS 0.3.1
cirros-0.3.5             x86_64     CirrOS 0.3.5
debian-6                 x86_64     Debian 6 (Squeeze)
debian-7                 sparc64    Debian 7 (Wheezy) (sparc64)
debian-7                 x86_64     Debian 7 (wheezy)
debian-8                 x86_64     Debian 8 (jessie)
debian-9                 x86_64     Debian 9 (stretch)
fedora-18                x86_64     Fedora® 18
fedora-19                x86_64     Fedora® 19
fedora-20                x86_64     Fedora® 20
fedora-21                aarch64    Fedora® 21 Server (aarch64)
fedora-21                armv7l     Fedora® 21 Server (armv7l)
fedora-21                ppc64      Fedora® 21 Server (ppc64)
fedora-21                ppc64le    Fedora® 21 Server (ppc64le)
fedora-21                x86_64     Fedora® 21 Server
fedora-22                aarch64    Fedora® 22 Server (aarch64)
fedora-22                armv7l     Fedora® 22 Server (armv7l)
fedora-22                i686       Fedora® 22 Server (i686)
fedora-22                x86_64     Fedora® 22 Server
fedora-23                aarch64    Fedora® 23 Server (aarch64)
fedora-23                armv7l     Fedora® 23 Server (armv7l)
fedora-23                i686       Fedora® 23 Server (i686)
fedora-23                ppc64      Fedora® 23 Server (ppc64)
fedora-23                ppc64le    Fedora® 23 Server (ppc64le)
fedora-23                x86_64     Fedora® 23 Server
fedora-24                aarch64    Fedora® 24 Server (aarch64)
fedora-24                armv7l     Fedora® 24 Server (armv7l)
fedora-24                i686       Fedora® 24 Server (i686)
fedora-24                x86_64     Fedora® 24 Server
fedora-25                aarch64    Fedora® 25 Server (aarch64)
fedora-25                armv7l     Fedora® 25 Server (armv7l)
fedora-25                i686       Fedora® 25 Server (i686)
fedora-25                ppc64      Fedora® 25 Server (ppc64)
fedora-25                ppc64le    Fedora® 25 Server (ppc64le)
fedora-25                x86_64     Fedora® 25 Server
fedora-26                aarch64    Fedora® 26 Server (aarch64)
fedora-26                armv7l     Fedora® 26 Server (armv7l)
fedora-26                i686       Fedora® 26 Server (i686)
fedora-26                ppc64      Fedora® 26 Server (ppc64)
fedora-26                ppc64le    Fedora® 26 Server (ppc64le)
fedora-26                x86_64     Fedora® 26 Server
fedora-27                aarch64    Fedora® 27 Server (aarch64)
fedora-27                armv7l     Fedora® 27 Server (armv7l)
fedora-27                i686       Fedora® 27 Server (i686)
fedora-27                ppc64      Fedora® 27 Server (ppc64)
fedora-27                ppc64le    Fedora® 27 Server (ppc64le)
fedora-27                x86_64     Fedora® 27 Server
fedora-28                i686       Fedora® 28 Server (i686)
fedora-28                x86_64     Fedora® 28 Server
freebsd-11.1             x86_64     FreeBSD 11.1
scientificlinux-6        x86_64     Scientific Linux 6.5
ubuntu-10.04             x86_64     Ubuntu 10.04 (Lucid)
ubuntu-12.04             x86_64     Ubuntu 12.04 (Precise)
ubuntu-14.04             x86_64     Ubuntu 14.04 (Trusty)
ubuntu-16.04             x86_64     Ubuntu 16.04 (Xenial)
ubuntu-18.04             x86_64     Ubuntu 18.04 (bionic)
opensuse-13.1            x86_64     openSUSE 13.1
opensuse-13.2            x86_64     openSUSE 13.2
opensuse-42.1            x86_64     openSUSE Leap 42.1
opensuse-tumbleweed      x86_64     openSUSE Tumbleweed

5. Create Virtual Machine OS-es from scratch with virt-builder

Below we'll create two images one for Fedora 28 and 1 for Debian 9 using the virt-builder (a tool to build virtual images quickly), the images that could be used are shown through below virt-builder –list command.

# iso='fedora-28';
# iso1='debian-9';


# sudo virt-builder $iso \
     –size=10G \
     –format qcow2 -o /var/lib/libvirt/images/$iso-vm1.qcow2 \
     –hostname $iso-vm1 \
     –network \
     –timezone Europe/Sofia


[   3.3] Downloading:
[   5.2] Planning how to build this image
[   5.2] Uncompressing
[  20.8] Resizing (using virt-resize) to expand the disk to 10.0G
[  50.8] Opening the new disk
[  53.7] Setting a random seed
[  53.7] Setting the hostname: fedora-28-vm1
[  53.7] Setting the timezone: Europe/Sofia
[  53.7] Setting passwords
virt-builder: Setting random password of root to YMTkxaJIkEU24Ytf

[  54.7] Finishing off
                   Output file: /var/lib/libvirt/images/fedora-28-vm1.qcow2
                   Output size: 10.0G
                 Output format: qcow2
            Total usable space: 9.3G
                    Free space: 8.2G (87%)


# sudo virt-builder $iso1 \
     –size=10G \
     –format qcow2 -o /var/lib/libvirt/images/$iso-vm1.qcow2 \
     –hostname $iso1-vm1 \
     –network \
     –timezone Europe/Sofia


[   3.2] Downloading:
[   4.1] Planning how to build this image
[   4.1] Uncompressing
[  16.9] Resizing (using virt-resize) to expand the disk to 10.0G
[  40.1] Opening the new disk
[  42.9] Setting a random seed
virt-builder: warning: random seed could not be set for this type of guest
[  42.9] Setting the hostname: debian-9-vm1
[  43.6] Setting the timezone: Europe/Sofia
[  43.6] Setting passwords
virt-builder: Setting random password of root to JtzEYGff9KxL5jCR
[  44.3] Finishing off
                   Output file: /var/lib/libvirt/images/debian-9-vm1.qcow2
                   Output size: 10.0G
                 Output format: qcow2
            Total usable space: 9.8G
                    Free space: 9.0G (91%)

vim bridged.xml

  <forward mode="bridge"/>
  <bridge name="br0"/>


# sudo virsh net-define –file bridged.xml
# sudo virsh net-autostart br0
# sudo virsh net-start br0


Above two commands will download pre-packaged KVM isos and store them inside /var/lib/libvirt/images/ you see also the root (administrator) password for both ISOs printed out.


root@jeremiah:/home/hipo/kvm# ls -ld /var/lib/libvirt/images/*
-rw-r–r– 1 root         root         10739318784 Oct 12 23:45 /var/lib/libvirt/images/debian-9-vm1.qcow2
-rw-r–r– 1 root         root         10739318784 Oct 12 23:46 /var/lib/libvirt/images/fedora-28-vm1.qcow2


To access directly the new created VMs as we have specified the –vnc option it is possible to directly vnc to the new host with VNC client (in linux I use vncviewer), on Windows you can use something like TightVNC.

6. Use official Linux distributions ISO boot files to install into KVM VM

Those who would like to run inside KVM VM Linux could do it directly using installable ISO files and install the set of Linux with the required packages, just like installing a fresh new Linux on a bare-metal machine.
To do so download your ISO image from the net (either from official distro website or a mirror website, in case if you need to spin an older version) and use virt-install to run the installer inside KVM.


root@jeremiah:~# cd /var/lib/libvirt/boot/;
root@jeremiah:~# wget


# sudo virt-install \
–virt-type=kvm \
–name centos7 \
–ram 2048 \
–vcpus=2 \
–os-variant=centos7.0 \
–virt-type=kvm \
–hvm \
–cdrom=/var/lib/libvirt/boot/CentOS-7-x86_64-DVD-1804.iso \
–network=bridge=br0,model=virtio \
–network=bridge=br1,model=virtio \
–graphics vnc \
–disk path=/var/lib/libvirt/images/centos7.qcow2,size=40,bus=virtio,format=qcow2

7. List newly created VMs with Virsh command


root@jeremiah:/home/hipo/kvm# virsh list –all
 Id    Name                           State
 3     fedora-28                      running
 –     debian9                        shut off


The –all parameter lists all available VMs ready to spin, if you want to check what are the VMs that are only running use instead:


root@jeremiah:/home/hipo/kvm# virsh list
 Id    Name                           State
 3     fedora-28                      running


8. Install Virtual Machine OS-es

Below lines will install 2 Virtual machines one Fedora 28 and Debian 9


virt-install –import –name $os \
    –ram 2048 \
    –vcpu 2 \
    –disk path=/var/lib/libvirt/images/$os-vm1.qcow2,format=qcow2 \
    –os-variant fedora-unknown \
    –network=bridge=br0,model=virtio \
    –noautoconsole \
  –hvm \
  –graphics vnc

virt-install –import –name $os     \
–ram 2048     \
–vcpu 2     \
–disk path=/var/lib/libvirt/images/$os-vm1.qcow2,format=qcow2     \
–os-variant debian9     –network=bridge=br0,model=virtio     \
–noautoconsole \
–hvm \
–graphics vnc

To deploy more just change the virtual machine type in os variable and modify the –os-variant variable to match the distribution name, to get the correct –os-variant variables that can be passed use osinfo-query below is output of the cmd:


root@jeremiah:/home/hipo/kvm# osinfo-query os
 Short ID             | Name                                               | Version  | ID                                      
 altlinux1.0          | Mandrake RE Spring 2001                            | 1.0      |        
 altlinux2.0          | ALT Linux 2.0                                      | 2.0      |        
 altlinux2.2          | ALT Linux 2.2                                      | 2.2      |        
 altlinux2.4          | ALT Linux 2.4                                      | 2.4      |        
 altlinux3.0          | ALT Linux 3.0                                      | 3.0      |        
 altlinux4.0          | ALT Linux 4.0                                      | 4.0      |        
 altlinux4.1          | ALT Linux 4.1                                      | 4.1      |        
 altlinux5.0          | ALT Linux 5.0                                      | 5.0      |        
 altlinux6.0          | ALT Linux 6.0                                      | 6.0      |        
 altlinux7.0          | ALT Linux 7.0                                      | 7.0      |        
 centos6.0            | CentOS 6.0                                         | 6.0      |            
 centos6.1            | CentOS 6.1                                         | 6.1      |            
 centos6.2            | CentOS 6.2                                         | 6.2      |            
 centos6.3            | CentOS 6.3                                         | 6.3      |            
 centos6.4            | CentOS 6.4                                         | 6.4      |            
 centos6.5            | CentOS 6.5                                         | 6.5      |            
 centos6.6            | CentOS 6.6                                         | 6.6      |            
 centos6.7            | CentOS 6.7                                         | 6.7      |            
 centos6.8            | CentOS 6.8                                         | 6.8      |            
 centos6.9            | CentOS 6.9                                         | 6.9      |            
 centos7.0            | CentOS 7.0                                         | 7.0      |            
 debian1.1            | Debian Buzz                                        | 1.1      |            
 debian1.2            | Debian Rex                                         | 1.2      |            
 debian1.3            | Debian Bo                                          | 1.3      |            
 debian2.0            | Debian Hamm                                        | 2.0      |            
 debian2.1            | Debian Slink                                       | 2.1      |            
 debian2.2            | Debian Potato                                      | 2.2      |            
 debian3              | Debian Woody                                       | 3        |              
 debian3.1            | Debian Sarge                                       | 3.1      |            
 debian4              | Debian Etch                                        | 4        |              
 debian5              | Debian Lenny                                       | 5        |              
 debian6              | Debian Squeeze                                     | 6        |              
 debian7              | Debian Wheezy                                      | 7        |              
 debian8              | Debian Jessie                                      | 8        |              
 debian9              | Debian Stretch                                     | 9        |              
 debiantesting        | Debian Testing                                     | testing  |        
 fedora-unknown       | Fedora                                             | unknown  |
 fedora1              | Fedora Core 1                                      | 1        |       
 fedora10             | Fedora 10                                          | 10       |      
 fedora11             | Fedora 11                                          | 11       |      
 fedora12             | Fedora 12                                          | 12       |      
 fedora13             | Fedora 13                                          | 13       |      
 fedora14             | Fedora 14                                          | 14       |      
 fedora15             | Fedora 15                                          | 15       |      
 fedora16             | Fedora 16                                          | 16       |      
 fedora17             | Fedora 17                                          | 17       |      
 fedora18             | Fedora 18                                          | 18       |      
 fedora19             | Fedora 19                                          | 19       |      
 fedora2              | Fedora Core 2                                      | 2        |       
 fedora20             | Fedora 20                                          | 20       |      
 fedora21             | Fedora 21                                          | 21       |      
 fedora22             | Fedora 22                                          | 22       |      
 fedora23             | Fedora 23                                          | 23       |      
 fedora24             | Fedora 24                                          | 24       |      
 fedora25             | Fedora 25                                          | 25       |      
 fedora26             | Fedora 26                                          | 26       |      
 fedora3              | Fedora Core 3                                      | 3        |       
 fedora4              | Fedora Core 4                                      | 4        |       
 fedora5              | Fedora Core 5                                      | 5        |       
 fedora6              | Fedora Core 6                                      | 6        |       
 fedora7              | Fedora 7                                           | 7        |       
 fedora8              | Fedora 8                                           | 8        |       
 fedora9              | Fedora 9                                           | 9        |       
 freebsd1.0           | FreeBSD 1.0                                        | 1.0      |          
 freebsd10.0          | FreeBSD 10.0                                       | 10.0     |         
 freebsd10.1          | FreeBSD 10.1                                       | 10.1     |         
 freebsd10.2          | FreeBSD 10.2                                       | 10.2     |         
 freebsd10.3          | FreeBSD 10.3                                       | 10.3     |         
 freebsd10.4          | FreeBSD 10.4                                       | 10.4     |         
 freebsd11.0          | FreeBSD 11.0                                       | 11.0     |         
 freebsd11.1          | FreeBSD 11.1                                       | 11.1     |         
 freebsd2.0           | FreeBSD 2.0                                        | 2.0      |          
 freebsd2.0.5         | FreeBSD 2.0.5                                      | 2.0.5    |        
 freebsd2.2.8         | FreeBSD 2.2.8                                      | 2.2.8    |        
 freebsd2.2.9         | FreeBSD 2.2.9                                      | 2.2.9    |        
 freebsd3.0           | FreeBSD 3.0                                        | 3.0      |          
 freebsd3.2           | FreeBSD 3.2                                        | 3.2      |          
 freebsd4.0           | FreeBSD 4.0                                        | 4.0      |          
 freebsd4.1           | FreeBSD 4.1                                        | 4.1      |          
 freebsd4.10          | FreeBSD 4.10                                       | 4.10     |         
 freebsd4.11          | FreeBSD 4.11                                       | 4.11     |         
 freebsd4.2           | FreeBSD 4.2                                        | 4.2      |          
 freebsd4.3           | FreeBSD 4.3                                        | 4.3      |          
 freebsd4.4           | FreeBSD 4.4                                        | 4.4      |          
 freebsd4.5           | FreeBSD 4.5                                        | 4.5      |          
 freebsd4.6           | FreeBSD 4.6                                        | 4.6      |          
 freebsd4.7           | FreeBSD 4.7                                        | 4.7      |          
 freebsd4.8           | FreeBSD 4.8                                        | 4.8      |          
 freebsd4.9           | FreeBSD 4.9                                        | 4.9      |          
 freebsd5.0           | FreeBSD 5.0                                        | 5.0      |          
 freebsd5.1           | FreeBSD 5.1                                        | 5.1      |          
 freebsd5.2           | FreeBSD 5.2                                        | 5.2      |          
 freebsd5.2.1         | FreeBSD 5.2.1                                      | 5.2.1    |        
 freebsd5.3           | FreeBSD 5.3                                        | 5.3      |          
 freebsd5.4           | FreeBSD 5.4                                        | 5.4      |          
 freebsd5.5           | FreeBSD 5.5                                        | 5.5      |          
 freebsd6.0           | FreeBSD 6.0                                        | 6.0      |          
 freebsd6.1           | FreeBSD 6.1                                        | 6.1      |          
 freebsd6.2           | FreeBSD 6.2                                        | 6.2      |          
 freebsd6.3           | FreeBSD 6.3                                        | 6.3      |          
 freebsd6.4           | FreeBSD 6.4                                        | 6.4      |          
 freebsd7.0           | FreeBSD 7.0                                        | 7.0      |          
 freebsd7.1           | FreeBSD 7.1                                        | 7.1      |          
 freebsd7.2           | FreeBSD 7.2                                        | 7.2      |          
 freebsd7.3           | FreeBSD 7.3                                        | 7.3      |          
 freebsd7.4           | FreeBSD 7.4                                        | 7.4      |          
 freebsd8.0           | FreeBSD 8.0                                        | 8.0      |          
 freebsd8.1           | FreeBSD 8.1                                        | 8.1      |          
 freebsd8.2           | FreeBSD 8.2                                        | 8.2      |          
 freebsd8.3           | FreeBSD 8.3                                        | 8.3      |          
 freebsd8.4           | FreeBSD 8.4                                        | 8.4      |          
 freebsd9.0           | FreeBSD 9.0                                        | 9.0      |          
 freebsd9.1           | FreeBSD 9.1                                        | 9.1      |          
 freebsd9.2           | FreeBSD 9.2                                        | 9.2      |          
 freebsd9.3           | FreeBSD 9.3                                        | 9.3      |          
 freedos1.2           | FreeDOS 1.2                                        | 1.2      |          
 gnome-continuous-3.10 | GNOME 3.10                                         | 3.10     |  
 gnome-continuous-3.12 | GNOME 3.12                                         | 3.12     |  
 gnome-continuous-3.14 | GNOME 3.14                                         | 3.14     |  
 gnome3.6             | GNOME 3.6                                          | 3.6      |              
 gnome3.8             | GNOME 3.8                                          | 3.8      |              
 macosx10.0           | MacOS X Cheetah                                    | 10.0     |            
 macosx10.1           | MacOS X Puma                                       | 10.1     |            
 macosx10.2           | MacOS X Jaguar                                     | 10.2     |            
 macosx10.3           | MacOS X Panther                                    | 10.3     |            
 macosx10.4           | MacOS X Tiger                                      | 10.4     |            
 macosx10.5           | MacOS X Leopard                                    | 10.5     |            
 macosx10.6           | MacOS X Snow Leopard                               | 10.6     |            
 macosx10.7           | MacOS X Lion                                       | 10.7     |            
 mageia1              | Mageia 1                                           | 1        |              
 mageia2              | Mageia 2                                           | 2        |              
 mageia3              | Mageia 3                                           | 3        |              
 mageia4              | Mageia 4                                           | 4        |              
 mageia5              | Mageia 5                                           | 5        |              
 mageia6              | Mageia 6                                           | 6        |              
 mandrake10.0         | Mandrake Linux 10.0                                | 10.0     |       
 mandrake10.1         | Mandrake Linux 10.1                                | 10.1     |       
 mandrake10.2         | Mandrake Linux 10.2                                | 10.2     |       
 mandrake5.1          | Mandrake Linux 5.1                                 | 5.1      |        
 mandrake5.2          | Mandrake Linux 5.2                                 | 5.2      |        
 mandrake5.3          | Mandrake Linux 5.3                                 | 5.3      |        
 mandrake6.0          | Mandrake Linux 6.0                                 | 6.0      |        
 mandrake6.1          | Mandrake Linux 6.1                                 | 6.1      |        
 mandrake7.0          | Mandrake Linux 7.0                                 | 7.0      |        
 mandrake7.1          | Mandrake Linux 7.1                                 | 7.1      |        
 mandrake7.2          | Mandrake Linux 7.2                                 | 7.2      |        
 mandrake8.0          | Mandrake Linux 8.0                                 | 8.0      |        
 mandrake8.1          | Mandrake Linux 8.1                                 | 8.1      |        
 mandrake8.2          | Mandrake Linux 8.2                                 | 8.2      |        
 mandrake9.0          | Mandrake Linux 9.0                                 | 9.0      |        
 mandrake9.1          | Mandrake Linux 9.1                                 | 9.1      |        
 mandrake9.2          | Mandrake Linux 9.2                                 | 9.2      |        
 mandriva2006.0       | Mandriva Linux 2006.0                              | 2006.0   |     
 mandriva2007         | Mandriva Linux 2007                                | 2007     |       
 mandriva2007.1       | Mandriva Linux 2007 Spring                         | 2007.1   |     
 mandriva2008.0       | Mandriva Linux 2008                                | 2008.0   |     
 mandriva2008.1       | Mandriva Linux 2008 Spring                         | 2008.1   |     
 mandriva2009.0       | Mandriva Linux 2009                                | 2009.0   |     
 mandriva2009.1       | Mandriva Linux 2009 Spring                         | 2009.1   |     
 mandriva2010.0       | Mandriva Linux 2010                                | 2010.0   |     
 mandriva2010.1       | Mandriva Linux 2010 Spring                         | 2010.1   |     
 mandriva2010.2       | Mandriva Linux 2010.2                              | 2010.2   |     
 mandriva2011         | Mandriva Linux 2011                                | 2011     |       
 mbs1.0               | Mandriva Business Server 1.0                       | 1.0      |             
 mes5                 | Mandriva Enterprise Server 5.0                     | 5.0      |             
 mes5.1               | Mandriva Enterprise Server 5.1                     | 5.1      |             
 msdos6.22            | Microsoft MS-DOS 6.22                              | 6.22     |         
 netbsd0.8            | NetBSD 0.8                                         | 0.8      |            
 netbsd0.9            | NetBSD 0.9                                         | 0.9      |            
 netbsd1.0            | NetBSD 1.0                                         | 1.0      |            
 netbsd1.1            | NetBSD 1.1                                         | 1.1      |            
 netbsd1.2            | NetBSD 1.2                                         | 1.2      |            
 netbsd1.3            | NetBSD 1.3                                         | 1.3      |            
 netbsd1.4            | NetBSD 1.4                                         | 1.4      |            
 netbsd1.5            | NetBSD 1.5                                         | 1.5      |            
 netbsd1.6            | NetBSD 1.6                                         | 1.6      |            
 netbsd2.0            | NetBSD 2.0                                         | 2.0      |            
 netbsd3.0            | NetBSD 3.0                                         | 3.0      |            
 netbsd4.0            | NetBSD 4.0                                         | 4.0      |            
 netbsd5.0            | NetBSD 5.0                                         | 5.0      |            
 netbsd5.1            | NetBSD 5.1                                         | 5.1      |            
 netbsd6.0            | NetBSD 6.0                                         | 6.0      |            
 netbsd6.1            | NetBSD 6.1                                         | 6.1      |            
 netbsd7.0            | NetBSD 7.0                                         | 7.0      |            
 netbsd7.1            | NetBSD 7.1                                         | 7.1      |            
 netbsd7.1.1          | NetBSD 7.1.1                                       | 7.1.1    |          
 netware4             | Novell Netware 4                                   | 4        |             
 netware5             | Novell Netware 5                                   | 5        |             
 netware6             | Novell Netware 6                                   | 6        |             
 openbsd4.2           | OpenBSD 4.2                                        | 4.2      |          
 openbsd4.3           | OpenBSD 4.3                                        | 4.3      |          
 openbsd4.4           | OpenBSD 4.4                                        | 4.4      |          
 openbsd4.5           | OpenBSD 4.5                                        | 4.5      |          
 openbsd4.8           | OpenBSD 4.8                                        | 4.8      |          
 openbsd4.9           | OpenBSD 4.9                                        | 4.9      |          
 openbsd5.0           | OpenBSD 5.0                                        | 5.0      |          
 openbsd5.1           | OpenBSD 5.1                                        | 5.1      |          
 openbsd5.2           | OpenBSD 5.2                                        | 5.2      |          
 openbsd5.3           | OpenBSD 5.3                                        | 5.3      |          
 openbsd5.4           | OpenBSD 5.4                                        | 5.4      |          
 openbsd5.5           | OpenBSD 5.5                                        | 5.5      |          
 openbsd5.6           | OpenBSD 5.6                                        | 5.6      |          
 openbsd5.7           | OpenBSD 5.7                                        | 5.7      |          
 openbsd5.8           | OpenBSD 5.8                                        | 5.8      |          
 openbsd5.9           | OpenBSD 5.9                                        | 5.9      |          
 openbsd6.0           | OpenBSD 6.0                                        | 6.0      |          
 openbsd6.1           | OpenBSD 6.1                                        | 6.1      |          
 openbsd6.2           | OpenBSD 6.2                                        | 6.2      |          
 opensolaris2009.06   | OpenSolaris 2009.06                                | 2009.06  |      
 opensuse-factory     | openSUSE                                           | factory  |    
 opensuse-unknown     | openSUSE                                           | unknown  |    
 opensuse10.2         | openSUSE 10.2                                      | 10.2     |       
 opensuse10.3         | openSUSE 10.3                                      | 10.3     |       
 opensuse11.0         | openSUSE 11.0                                      | 11.0     |       
 opensuse11.1         | openSUSE 11.1                                      | 11.1     |       
 opensuse11.2         | openSUSE 11.2                                      | 11.2     |       
 opensuse11.3         | openSUSE 11.3                                      | 11.3     |       
 opensuse11.4         | openSUSE 11.4                                      | 11.4     |       
 opensuse12.1         | openSUSE 12.1                                      | 12.1     |       
 opensuse12.2         | openSUSE 12.2                                      | 12.2     |       
 opensuse12.3         | openSUSE 12.3                                      | 12.3     |       
 opensuse13.1         | openSUSE 13.1                                      | 13.1     |       
 opensuse13.2         | openSUSE 13.2                                      | 13.2     |       
 opensuse42.1         | openSUSE Leap 42.1                                 | 42.1     |       
 opensuse42.2         | openSUSE Leap 42.2                                 | 42.2     |       
 opensuse42.3         | openSUSE Leap 42.3                                 | 42.3     |       
 opensusetumbleweed   | openSUSE Tumbleweed                                | tumbleweed |
 rhel-atomic-7.0      | Red Hat Enterprise Linux Atomic Host 7.0           | 7.0      |       
 rhel-atomic-7.1      | Red Hat Enterprise Linux Atomic Host 7.1           | 7.1      |       
 rhel-atomic-7.2      | Red Hat Enterprise Linux Atomic Host 7.2           | 7.2      |       
 rhel2.1              | Red Hat Enterprise Linux 2.1                       | 2.1      |              
 rhel2.1.1            | Red Hat Enterprise Linux 2.1 Update 1  
/etc/bind/masters/            | 2.1.1    |            
 rhel2.1.2            | Red Hat Enterprise Linux 2.1 Update 2              | 2.1.2    |            
 rhel2.1.3            | Red Hat Enterprise Linux 2.1 Update 3              | 2.1.3    |            
 rhel2.1.4            | Red Hat Enterprise Linux 2.1 Update 4              | 2.1.4    |            
 rhel2.1.5            | Red Hat Enterprise Linux 2.1 Update 5              | 2.1.5    |            
 rhel2.1.6            | Red Hat Enterprise Linux 2.1 Update 6              | 2.1.6    |            
 rhel2.1.7            | Red Hat Enterprise Linux 2.1 Update 7              | 2.1.7    |            
 rhel3                | Red Hat Enterprise Linux 3                         | 3        |                
 rhel3.1              | Red Hat Enterprise Linux 3 Update 1                | 3.1      |              
 rhel3.2              | Red Hat Enterprise Linux 3 Update 2                | 3.2      |              
 rhel3.3              | Red Hat Enterprise Linux 3 Update 3                | 3.3      |              
 rhel3.4              | Red Hat Enterprise Linux 3 Update 4                | 3.4      |              
 rhel3.5              | Red Hat Enterprise Linux 3 Update 5                | 3.5      |              
 rhel3.6              | Red Hat Enterprise Linux 3 Update 6                | 3.6      |              
 rhel3.7              | Red Hat Enterprise Linux 3 Update 7                | 3.7      |              
 rhel3.8              | Red Hat Enterprise Linux 3 Update 8                | 3.8      |              
 rhel3.9              | Red Hat Enterprise Linux 3 Update 9                | 3.9      |              
 rhel4.0              | Red Hat Enterprise Linux 4.0                       | 4.0      |              
 rhel4.1              | Red Hat Enterprise Linux 4.1                       | 4.1      |              
 rhel4.2              | Red Hat Enterprise Linux 4.2                       | 4.2      |              
 rhel4.3              | Red Hat Enterprise Linux 4.3                       | 4.3      |              
 rhel4.4              | Red Hat Enterprise Linux 4.4                       | 4.4      |              
 rhel4.5              | Red Hat Enterprise Linux 4.5                       | 4.5      |              
 rhel4.6              | Red Hat Enterprise Linux 4.6                       | 4.6      |              
 rhel4.7              | Red Hat Enterprise Linux 4.7                       | 4.7      |              
 rhel4.8              | Red Hat Enterprise Linux 4.8                       | 4.8      |              
 rhel4.9              | Red Hat Enterprise Linux 4.9                       | 4.9      |              
 rhel5.0              | Red Hat Enterprise Linux 5.0                       | 5.0      |              
 rhel5.1              | Red Hat Enterprise Linux 5.1                       | 5.1      |              
 rhel5.10             | Red Hat Enterprise Linux 5.10                      | 5.10     |             
 rhel5.11             | Red Hat Enterprise Linux 5.11                      | 5.11     |             
 rhel5.2              | Red Hat Enterprise Linux 5.2                       | 5.2      |              
 rhel5.3              | Red Hat Enterprise Linux 5.3                       | 5.3      |              
 rhel5.4              | Red Hat Enterprise Linux 5.4                       | 5.4      |              
 rhel5.5              | Red Hat Enterprise Linux 5.5                       | 5.5      |              
 rhel5.6              | Red Hat Enterprise Linux 5.6                       | 5.6      |              
 rhel5.7              | Red Hat Enterprise Linux 5.7                       | 5.7      |              
 rhel5.8              | Red Hat Enterprise Linux 5.8                       | 5.8      |              
 rhel5.9              | Red Hat Enterprise Linux 5.9                       | 5.9      |              
 rhel6.0              | Red Hat Enterprise Linux 6.0                       | 6.0      |              
 rhel6.1              | Red Hat Enterprise Linux 6.1                       | 6.1      |              
 rhel6.2              | Red Hat Enterprise Linux 6.2                       | 6.2      |              
 rhel6.3              | Red Hat Enterprise Linux 6.3                       | 6.3      |              
 rhel6.4              | Red Hat Enterprise Linux 6.4                       | 6.4      |              
 rhel6.5              | Red Hat Enterprise Linux 6.5                       | 6.5      |              
 rhel6.6              | Red Hat Enterprise Linux 6.6                       | 6.6      |              
 rhel6.7              | Red Hat Enterprise Linux 6.7                       | 6.7      |              
 rhel6.8              | Red Hat Enterprise Linux 6.8                       | 6.8      |              
 rhel6.9              | Red Hat Enterprise Linux 6.9                       | 6.9      |              
 rhel7.0              | Red Hat Enterprise Linux 7.0                       | 7.0      |              
 rhel7.1              | Red Hat Enterprise Linux 7.1                       | 7.1      |              
 rhel7.2              | Red Hat Enterprise Linux 7.2                       | 7.2      |              
 rhel7.3              | Red Hat Enterprise Linux 7.3                       | 7.3      |              
 rhel7.4              | Red Hat Enterprise Linux 7.4                       | 7.4      |              
 rhl1.0               | Red Hat Linux 1.0                                  | 1.0      |               
 rhl1.1               | Red Hat Linux 1.1                                  | 1.1      |               
 rhl2.0               | Red Hat Linux 2.0                                  | 2.0      |               
 rhl2.1               | Red Hat Linux 2.1                                  | 2.1      |               
 rhl3.0.3             | Red Hat Linux 3.0.3                                | 3.0.3    |             
 rhl4.0               | Red Hat Linux 4.0                                  | 4.0      |               
 rhl4.1               | Red Hat Linux 4.1                                  | 4.1      |               
 rhl4.2               | Red Hat Linux 4.2                                  | 4.2      |               
 rhl5.0               | Red Hat Linux 5.0                                  | 5.0      |               
 rhl5.1               | Red Hat Linux 5.1                                  | 5.1      |               
 rhl5.2               | Red Hat Linux 5.2                                  | 5.2      |               
 rhl6.0               | Red Hat Linux 6.0                                  | 6.0      |               
 rhl6.1               | Red Hat Linux 6.1                                  | 6.1      |               
 rhl6.2               | Red Hat Linux 6.2                                  | 6.2      |               
 rhl7                 | Red Hat Linux 7                                    | 7        |                 
 rhl7.1               | Red Hat Linux 7.1                                  | 7.1      |               
 rhl7.2               | Red Hat Linux 7.2                                  | 7.2      |               
 rhl7.3               | Red Hat Linux 7.3                                  | 7.3      |               
 rhl8.0               | Red Hat Linux 8.0                                  | 8.0      |               
 rhl9                 | Red Hat Linux 9                                    | 9        |                 
 sled10               | SUSE Linux Enterprise Desktop 10                   | 10       |                 
 sled10sp1            | SUSE Linux Enterprise Desktop 10 SP1               | 10.1     |               
 sled10sp2            | SUSE Linux Enterprise Desktop 10 SP2               | 10.2     |               
 sled10sp3            | SUSE Linux Enterprise Desktop 10 SP3               | 10.3     |               
 sled10sp4            | SUSE Linux Enterprise Desktop 10 SP4               | 10.4     |               
 sled11               | SUSE Linux Enterprise Desktop 11                   | 11       |                 
 sled11sp1            | SUSE Linux Enterprise Desktop 11 SP1               | 11.1     |               
 sled11sp2            | SUSE Linux Enterprise Desktop 11 SP2               | 11.2     |               
 sled11sp3            | SUSE Linux Enterprise Desktop 11 SP3               | 11.3     |               
 sled11sp4            | SUSE Linux Enterprise Desktop 11 SP4               | 11.4     |               
 sled12               | SUSE Linux Enterprise Desktop 12                   | 12       |                 
 sled12sp1            | SUSE Linux Enterprise Desktop 12 SP1               | 12.1     |               
 sled12sp2            | SUSE Linux Enterprise Desktop 12 SP2               | 12.2     |               
 sled9                | SUSE Linux Enterprise Desktop 9                    | 9        |                  
 sles10               | SUSE Linux Enterprise Server 10            
/etc/bind/masters/        | 10       |                 
 sles10sp1            | SUSE Linux Enterprise Server 10 SP1                | 10.1     |               
 sles10sp2            | SUSE Linux Enterprise Server 10 SP2                | 10.2     |               
 sles10sp3            | SUSE Linux Enterprise Server 10 SP3                | 10.3     |               
 sles10sp4            | SUSE Linux Enterprise Server 10 SP4                | 10.4     |               
 sles11               | SUSE Linux Enterprise Server 11                    | 11       |                 
 sles11sp1            | SUSE Linux Enterprise Server 11 SP1                | 11.1     |               
 sles11sp2            | SUSE Linux Enterprise Server 11 SP2                | 11.2     |               
 sles11sp3            | SUSE Linux Enterprise Server 11 SP3                | 11.3     |               
 sles11sp4            | SUSE Linux Enterprise Server 11 SP4                | 11.4     |               
 sles12               | SUSE Linux Enterprise Server 12                    | 12       |                 
 sles12sp1            | SUSE Linux Enterprise Server 12 SP1                | 12.1     |               
 sles12sp2            | SUSE Linux Enterprise Server 12 SP2                | 12.2     |               
 sles9                | SUSE Linux Enterprise Server 9                     | 9        |                  
 solaris10            | Solaris 10                                         | 10       |               
 solaris11            | Oracle Solaris 11                                  | 11       |            
 solaris9             | Solaris 9                                          | 9        |                
 ubuntu10.04          | Ubuntu 10.04 LTS                                   | 10.04    |          
 ubuntu10.10          | Ubuntu 10.10                                       | 10.10    |          
 ubuntu11.04          | Ubuntu 11.04                                       | 11.04    |          
 ubuntu11.10          | Ubuntu 11.10                                       | 11.10    |          
 ubuntu12.04          | Ubuntu 12.04 LTS                                   | 12.04    |          
 ubuntu12.10          | Ubuntu 12.10                                       | 12.10    |          
 ubuntu13.04          | Ubuntu 13.04                                       | 13.04    |          
 ubuntu13.10          | Ubuntu 13.10                                       | 13.10    |          
 ubuntu14.04          | Ubuntu 14.04 LTS                                   | 14.04    |          
 ubuntu14.10          | Ubuntu 14.10                                       | 14.10    |          
 ubuntu15.04          | Ubuntu 15.04                                       | 15.04    |          
 ubuntu15.10          | Ubuntu 15.10                                       | 15.10    |          
 ubuntu16.04          | Ubuntu 16.04                                       | 16.04    |          
 ubuntu16.10          | Ubuntu 16.10                                       | 16.10    |          
 ubuntu17.04          | Ubuntu 17.04                                       | 17.04    |          
 ubuntu17.10          | Ubuntu 17.10                                       | 17.10    |          
 ubuntu4.10           | Ubuntu 4.10                                        | 4.10     |           
 ubuntu5.04           | Ubuntu 5.04                                        | 5.04     |           
 ubuntu5.10           | Ubuntu 5.10                                        | 5.10     |           
 ubuntu6.06           | Ubuntu 6.06 LTS                                    | 6.06     |           
 ubuntu6.10           | Ubuntu 6.10                                        | 6.10     |           
 ubuntu7.04           | Ubuntu 7.04                                        | 7.04     |           
 ubuntu7.10           | Ubuntu 7.10                                        | 7.10     |           
 ubuntu8.04           | Ubuntu 8.04 LTS                                    | 8.04     |           
 ubuntu8.10           | Ubuntu 8.10                                        | 8.10     |           
 ubuntu9.04           | Ubuntu 9.04                                        | 9.04     |           
 ubuntu9.10           | Ubuntu 9.10                                        | 9.10     |           
 win1.0               | Microsoft Windows 1.0                              | 1.0      |            
 win10                | Microsoft Windows 10                               | 10.0     |             
 win2.0               | Microsoft Windows 2.0                              | 2.0      |            
 win2.1               | Microsoft Windows 2.1                              | 2.1      |            
 win2k                | Microsoft Windows 2000                             | 5.0      |             
 win2k12              | Microsoft Windows Server 2012                      | 6.3      |           
 win2k12r2            | Microsoft Windows Server 2012 R2                   | 6.3      |         
 win2k3               | Microsoft Windows Server 2003                      | 5.2      |            
 win2k3r2             | Microsoft Windows Server 2003 R2                   | 5.2      |          
 win2k8               | Microsoft Windows Server 2008                      | 6.0      |            
 win2k8r2             | Microsoft Windows Server 2008 R2                   | 6.1      |          
 win3.1               | Microsoft Windows 3.1                              | 3.1      |            
 win7                 | Microsoft Windows 7                                | 6.1      |              
 win8                 | Microsoft Windows 8                                | 6.2      |              
 win8.1               | Microsoft Windows 8.1                              | 6.3      |            
 win95                | Microsoft Windows 95                               | 4.0      |             
 win98                | Microsoft Windows 98                               | 4.1      |             
 winme                | Microsoft Windows Millennium Edition               | 4.9      |             
 winnt3.1             | Microsoft Windows NT Server 3.1                    | 3.1      |          
 winnt3.5             | Microsoft Windows NT Server 3.5                    | 3.5      |          
 winnt3.51            | Microsoft Windows NT Server 3.51                   | 3.51     |         
 winnt4.0             | Microsoft Windows NT Server 4.0                    | 4.0      |          
 winvista             | Microsoft Windows Vista                            | 6.0      |          
 winxp                | Microsoft Windows XP                               | 5.1      |  


9. Start / Stop listed KVM Virtual Machine


root@jeremiah:~# virsh list –all
 Id    Name                           State
 3     fedora-28                      running
 –     debian9                        shut off


To start debian9 linux virtual machine that is currently off


root@jeremiah:~# virsh start fedora-28
Domain fedora-28 started


root@jeremiah:/home/hipo# virsh start debian9
error: Failed to start domain debian9
error: Requested operation is not valid: network 'default' is not active

root@jeremiah:/home/hipo# virsh net-list –all
Name                 State      Autostart     Persistent
br0                  active     yes           yes
default              inactive   no            yes


root@jeremiah:/home/hipo# virsh net-start default
Network default started

root@jeremiah:/home/hipo# virsh start debian9
Domain debian9 started


10. Attach to running VM with virsh or virt-manager


root@jeremiah:~# virsh list
 Id    Name                           State
 1     fedora-28                      running
 3     debian9                        running

root@jeremiah:~# virsh connect debian9


Note that to make the login prompt appear you have to press enter once after the ^] connection string appears


An alternative way is to use virt-manager GUI KVM desktop management interface and click over the Virtual Machine Guest name, in same fashion like in VirtualBox.



If you have KVM running on your Linux desktop PC / notebook you can also connect via VNC with virsh command.


root@jericho:~# virsh vncdisplay centos7

Another handy thing is to expose the Virtualized Guest OS with VNC in order to be able to connect and manage installation or further Linux configuration via VNC using an SSH Tunnel with port forwarding:


$ ssh -L 5901:


11.  Start / Shutdown / Suspend / Reboot (safe reboot) a VM guest machine domain



root@jericho:~# virsh shutdown debian9
root@jericho:~# virsh start fedora-28
root@jericho:~# virsh suspend debian9
root@jericho:~# virsh reboot fedora-28


12. Remove / Delete KVM Virtual Machines domain


root@jeremiah:~# virsh undefine fedora-28
root@jeremiah:~# virsh destroy fedora-28

Closing words

Using KVM to experiment with different OS distributions is really fun just like you can easily run a number of the major most popular Linux Distributions and a set of different versions. It takes few minutes to have a fully functional Linux to play with and it saves a lot of hassles when dealing with GNU / Linux and FreeBSD, doing so in Virtualbox for me prooved to be much more complicated (not to mention that often Virtualbox had an ugly bugs so even Importing an Appliance as a Guest VM with an official distro OS-es failed with weird errors.
One other very practical use of Kerkel-based Virtualization is if you want to run your servers using own Micro-Services architecture (e.g. run multiple Linux OS-es each running a separate Apache / Nginx / MySQL / PostGreSQL / Backup / Storage) etc. all of it running on a single dedicated server or a self-hosted bare-metal
There are plenty of Web Interfaces for Management KVM (proprietary and free software) that could even futher simplify the use and deploy / destory of KVM VMs.
All that makes possible running your own Linux or Web hosting provider a relatively easy task and seriously could cut business expenses and operational (maintenance) costs.

If you plan to run youw own hosting company, I can help you establish your infrastructure and advise you on the right technologies to use.


FreeBSD Desktop: Allow All system users to mount CDROM, DVD, USB Devices and other external devices

Friday, November 16th, 2012

freebsd allow all system users to mount CD DVD USB in GNOME and KDE desktop - freebsd power to serve logo

Users who use FreeBSD for multiple logins Desktop host or in universities multiple login Desktop  shared user PCs will have problems with mounting CD and DVD Roms, Usbs and other external devices. To mount any of those a root or toor superuser  will be required and this makes a really bad impression to the novice users, making them think FreeBSD is user unfriendly, where in reality it was just build to behave so with higher security in mind.
This ruins a whole user GNOME experience and disappoints the end user, especially if the user is just a person who needs to do some browsing and copy few files from and to the host.
This prevents udevd and auto mount in GNOME and  KDE GUI environments to be unable to automatically mount and unmount CD / DVDs and USBS where plugged or unplugged but instead just poping up permission errors whether CD or USB is attached.
Thanksfully, you can change this behavior to make FreeBSD a bit more user friendly and of course 'less secure' by few simple commands 🙂

Here is how:

freebsd# sysctl -w vfs.usermount=1

vfs.usermount: 0 -> 1

echo 'vfs.usermount=1' >> /etc/sysctl.conf

What is required next is to add all devices which will be mountable by all users in /dev/devfs.conf.

To get a list of devices do:
freebsd# camcontrol devlist

at scbus0 target 0 lun 0 (pass0,da0) at scbus1 target 3 lun 0 (pass1,sa0) at scbus1 target 6 lun 0 (pass2,cd0) #

Most USB devices are recognized and assigned as /dev/da0, and almost all CD and DVD Rom devices will be initialized by kernel as /dev/cd0, however if you get something different just set the appropriate vals.

a) Add permission records for CD / DVD ROM in /etc/devfs.conf
freebsd# echo 'own /dev/da0 root:operator' >> /etc/devfs.conf
freebsd# echo 'perm /dev/da00 0666' >> /etc/devfs.conf

b) Add permission records for USBs in /dev/devfs.conf

freebsd# echo '## allow member of operator to mount cdrom' >> /etc/devfs.conf
freebsd# echo 'own /dev/cd0 root:operator' >> /etc/devfs.conf
freebsd# echo 'perm /dev/cd0 0660' >> /etc/devfs.conf

To allow, all present system users to have access to mount USB, CD / DVD roms, it is necessery to add all users to the operator, group. This is a security bad practice as this will make allow all users to have extra permissions to binaries on the system owned or allowed to be accessed by operator group. However for home computers, where you, your sister and a bunch of good friends have accounts, security shouldn't be of a great concern.

If you know well all your users and you have disabled SSH on the system and security is not of top priority run:

freebsd# /usr/local/bin/bash
root@freebsd~# for i in /home/*; do user=$(echo $i|sed -e 's#/home/##g'); do \
pw groupmod operator -m $user; \

Onwards, you can check few users to see to see if they are added to operator group

freebsd$ id
uid=1001(hipo) gid=1001(hipo) groups=1001(hipo),0(wheel),5(operator)

Well that's all now your GNOME hal process – (Hardware Abstraction Layer) will be able to manage CD / DVDs and USBs with no more weird errors.

This article was inspired by cybercity's Allow normal users to mount CDROMs DVDs and USB devices. So thanks 'em for being a source of inspiration.

Enjoy 🙂

Allow Directory Listing in Apache Webserver / Get around Directory index forbidden by Options directive

Thursday, October 4th, 2012

I have configured Apache VirtualHost, inside the VirtualHost hosted domain, it is supposed to be a directory, where Directory Listing has to be allowed. My VirtualHost configuration looks like so:

NameVirtualHost *

DocumentRoot /var/www
DirectoryIndex index.html index.htm index.php index.html.var

Options FollowSymLinks
AllowOverride All
Order allow,deny
allow from all

Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all

Options Indexes FollowSymLinks MultiViews
AllowOverride All
Order allow,deny
allow from all

ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/

AllowOverride None
Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
Order allow,deny
Allow from all

ErrorLog ${APACHE_LOG_DIR}/error.log
LogLevel warn
CustomLog ${APACHE_LOG_DIR}/access.log combined

I have a directory (/var/www/directory), there I store various files and I prefer this directory to be enabled to support Directory listing. I have the whole situation on Debian Linux. By default in Debian Apache is configured to disable directory listing for subdirectories to both default host and Virtualhosts

In order to enable /var/www/directory, accessed inside browser via web address I had to add inside my Virtualhost /etc/apache2/sites-available/ following Apache directive:

AddDefaultCharset UTF-8
Options FollowSymLinks Indexes
AllowOverride All

As you can see I included also AddDefaultCharset UTF-8, because inside /directory I have files in cyrillic and, if I don’t explicitly set the encoding to UTF-8, the htmls are improperly shown in browsers.

The exact directive that enables directory listing in Apache is:

Options Indexes

Setting Indexes to -Indexes disables directory listing, e.g.

Options -Indexes

BTW if you need to make certain directory accessible for default set Apache Options (permissions) should be set in /etc/apache2/apache2.conf

Options Indexes

This will set Apache directory permissions for all Virtualhost, useful if all virtualhosts share common ServerRoot and the directory has to be accessible via all vhosts.
Well that’s all Cheers 😉

How to prevent SSH and FTP bruteforce attacks with iptables on Linux

Friday, December 30th, 2011

Earlier I've blogged about how to prevent brute force attacks with fail2ban, denohosts and blockhosts , however there is easier way to secure against basic brute force attacks by not installing or configuring any external programs.
The way I'm talking about uses simple iptables rules to filter out brute force attacks.

Here is a small script to stop ssh and FTP invaders which try to initiate more than 3 consequential connections in 5 minutes time to port 22 or port 23:

/sbin/iptables -A INPUT -p tcp --dport 22 --syn -m recent --name sshbr --set
/sbin/iptables -A INPUT -p tcp --dport 22 --syn -j SSH_WHITELIST
/sbin/iptables -A INPUT -p tcp --dport 22 --syn -m recent --name sshbr \
--update --rttl --hitcount 3 --seconds 300 -j REJECT --reject-with tcp-reset
/sbin/iptables -A SSH_WHITELIST -s $SERVER_MAIN_IP -p tcp --dport 22 --syn -m recent --rttl --remove

The only thinIf the rules are matched iptables filter rules will be added to the iptables CHAIN SSH_WHITELIST
In case if you want to add some more truested IPs add some more iptables rules, like:

/sbin/iptables -A SSH_WHITELIST -s $ALLOW_IP -p tcp --dport 22 --syn -m recent --rttl --remove

Each filtered IP that matches the rules will be filtered for 5 minutes, if 5 minutes is enough, the 300 value has to be increased.