Posts Tagged ‘standard’

How to redirect TCP port traffic from Internet Public IP host to remote local LAN server, Redirect traffic for Apache Webserver, MySQL, or other TCP service to remote host

Thursday, September 23rd, 2021

 

 

Linux-redirect-forward-tcp-ip-port-traffic-from-internet-to-remote-internet-LAN-IP-server-rinetd-iptables-redir

 

 

1. Use the good old times rinetd – internet “redirection server” service


Perhaps, many people who are younger wouldn't remember rinetd's use was pretty common on old Linuxes in the age where iptables was not on the scene and its predecessor ipchains was so common.
In the raise of mass internet rinetd started loosing its popularity because the service was exposed to the outer world and due to security holes and many exploits circulating the script kiddie communities
many servers get hacked "pwned" in the jargon of the script kiddies.

rinetd is still available even in modern Linuxes and over the last years I did not heard any severe security concerns regarding it, but the old paranoia perhaps and the set to oblivion makes it still unpopular soluttion for port redirect today in year 2021.
However for a local secured DMZ lans I can tell you that its use is mostly useful and I chooes to use it myself, everynow and then due to its simplicity to configure and use.
rinetd is pretty standard among unixes and is also available in old Sun OS / Solaris and BSD-es and pretty much everything on the Unix scene.

Below is excerpt from 'man rinetd':

 

DESCRIPTION
     rinetd redirects TCP connections from one IP address and port to another. rinetd is a single-process server which handles any number of connections to the address/port pairs
     specified in the file /etc/rinetd.conf.  Since rinetd runs as a single process using nonblocking I/O, it is able to redirect a large number of connections without a severe im‐
     pact on the machine. This makes it practical to run TCP services on machines inside an IP masquerading firewall. rinetd does not redirect FTP, because FTP requires more than
     one socket.
     rinetd is typically launched at boot time, using the following syntax:      /usr/sbin/rinetd      The configuration file is found in the file /etc/rinetd.conf, unless another file is specified using the -c command line option.

To use rinetd on any LInux distro you have to install and enable it with apt or yum as usual. For example on my Debian GNU / Linux home machine to use it I had to install .deb package, enable and start it it via systemd :

 

server:~# apt install –yes rinetd

server:~#  systemctl enable rinetd


server:~#  systemctl start rinetd


server:~#  systemctl status rinetd
● rinetd.service
   Loaded: loaded (/etc/init.d/rinetd; generated)
   Active: active (running) since Tue 2021-09-21 10:48:20 EEST; 2 days ago
     Docs: man:systemd-sysv-generator(8)
    Tasks: 1 (limit: 4915)
   Memory: 892.0K
   CGroup: /system.slice/rinetd.service
           └─1364 /usr/sbin/rinetd


rinetd is doing the traffic redirect via a separate process daemon, in order for it to function once you have service up check daemon is up as well.

root@server:/home/hipo# ps -ef|grep -i rinet
root       359     1  0 16:10 ?        00:00:00 /usr/sbin/rinetd
root       824 26430  0 16:10 pts/0    00:00:00 grep -i rinet

+ Configuring a new port redirect with rinetd

 

Is pretty straight forward everything is handled via one single configuration – /etc/rinetd.conf

The format (syntax) of a forwarding rule is as follows:

     [bindaddress] [bindport] [connectaddress] [connectport]


Besides that rinetd , could be used as a primitive firewall substitute to iptables, general syntax of allow deny an IP address is done with (allow, deny) keywords:
 

allow 192.168.2.*
deny 192.168.2.1?


To enable logging to external file ,you'll have to include in the configuration:

# logging information
logfile /var/log/rinetd.log

Here is an example rinetd.conf configuration, redirecting tcp mysql 3306, nginx on port 80 and a second web service frontend for ILO to server reachable via port 8888 and a redirect from External IP to local IP SMTP server.

 

#
# this is the configuration file for rinetd, the internet redirection server
#
# you may specify global allow and deny rules here
# only ip addresses are matched, hostnames cannot be specified here
# the wildcards you may use are * and ?
#
# allow 192.168.2.*
# deny 192.168.2.1?


#
# forwarding rules come here
#
# you may specify allow and deny rules after a specific forwarding rule
# to apply to only that forwarding rule
#
# bindadress    bindport  connectaddress  connectport


# logging information
logfile /var/log/rinetd.log
83.228.93.76        80            192.168.0.20       80
192.168.0.2        3306            192.168.0.19        3306
83.228.93.76        443            192.168.0.20       443
# enable for access to ILO
83.228.93.76        8888            192.168.1.25 443

127.0.0.1    25    192.168.0.19    25


83.228.93.76 is my external ( Public )  IP internet address where 192.168.0.20, 192.168.0.19, 192.168.0.20 (are the DMZ-ed Lan internal IPs) with various services.

To identify the services for which rinetd is properly configured to redirect / forward traffic you can see it with netstat or the newer ss command
 

root@server:/home/hipo# netstat -tap|grep -i rinet
tcp        0      0 www.pc-freak.net:8888   0.0.0.0:*               LISTEN      13511/rinetd      
tcp        0      0 www.pc-freak.n:http-alt 0.0.0.0:*               LISTEN      21176/rinetd        
tcp        0      0 www.pc-freak.net:443   0.0.0.0:*               LISTEN      21176/rinetd      

 

+ Using rinetd to redirect External interface IP to loopback's port (127.0.0.1)

 

If you have the need to redirect an External connectable living service be it apache mysql / privoxy / squid or whatever rinetd is perhaps the tool of choice (especially since there is no way to do it with iptables.

If you want to redirect all traffic which is accessed via Linux's loopback interface (localhost) to be reaching a remote host 11.5.8.1 on TCP port 1083 and 1888, use below config

# bindadress    bindport  connectaddress  connectport
11.5.8.1        1083            127.0.0.1       1083
11.5.8.1        1888            127.0.0.1       1888

 

For a quick and dirty solution to redirect traffic rinetd is very useful, however you'll have to keep in mind that if you want to redirect traffic for tens of thousands of connections constantly originating from the internet you might end up with some disconnects as well as notice a increased use of rinetd CPU use with the incrased number of forwarded connections.

 

2. Redirect TCP / IP port using DNAT iptables firewall rules

 

Lets say you have some proxy, webservice or whatever service running on port 5900 to be redirected with iptables.
The easeiest legacy way is to simply add the redirection rules to /etc/rc.local​. In newer Linuxes rc.local so if you decide to use,
you'll have to enable rc.local , I've written earlier a short article on how to enable rc.local on newer Debian, Fedora, CentOS

 

# redirect 5900 TCP service 
sysctl -w net.ipv4.conf.all.route_localnet=1
iptables -t nat -I PREROUTING -p tcp –dport 5900 -j REDIRECT –to-ports 5900
iptables -t nat -I OUTPUT -p tcp -o lo –dport 5900 -j REDIRECT –to-ports 5900
iptables -t nat -A OUTPUT -o lo -d 127.0.0.1 -p tcp –dport 5900 -j DNAT  –to-destination 192.168.1.8:5900
iptables -t nat -I OUTPUT –source 0/0 –destination 0/0 -p tcp –dport 5900 -j REDIRECT –to-ports 5900

 

Here is another two example which redirects port 2208 (which has configured a bind listener for SSH on Internal host 192.168.0.209:2208) from External Internet IP address (XXX.YYY.ZZZ.XYZ) 
 

# Port redirect for SSH to VM on openxen internal Local lan server 192.168.0.209 
-A PREROUTING  -p tcp –dport 2208 -j DNAT –to-destination 192.168.0.209:2208
-A POSTROUTING -p tcp –dst 192.168.0.209 –dport 2208 -j SNAT –to-source 83.228.93.76

 

3. Redirect TCP traffic connections with redir tool

 

If you look for an easy straight forward way to redirect TCP traffic, installing and using redir (ready compiled program) might be a good idea.


root@server:~# apt-cache show redir|grep -i desc -A5 -B5
Version: 3.2-1
Installed-Size: 60
Maintainer: Lucas Kanashiro <kanashiro@debian.org>
Architecture: amd64
Depends: libc6 (>= 2.15)
Description-en: Redirect TCP connections
 It can run under inetd or stand alone (in which case it handles multiple
 connections).  It is 8 bit clean, not limited to line mode, is small and
 light. Supports transparency, FTP redirects, http proxying, NAT and bandwidth
 limiting.
 .
 redir is all you need to redirect traffic across firewalls that authenticate
 based on an IP address etc. No need for the firewall toolkit. The
 functionality of inetd/tcpd and "redir" will allow you to do everything you
 need without screwy telnet/ftp etc gateways. (I assume you are running IP
 Masquerading of course.)

Description-md5: 2089a3403d126a5a0bcf29b22b68406d
Homepage: https://github.com/troglobit/redir
Tag: interface::daemon, network::server, network::service, role::program,
 use::proxying
Section: net
Priority: optional

 

 

server:~# apt-get install –yes redir

Here is a short description taken from its man page 'man redir'

 

DESCRIPTION
     redir redirects TCP connections coming in on a local port, [SRC]:PORT, to a specified address/port combination, [DST]:PORT.  Both the SRC and DST arguments can be left out,
     redir will then use 0.0.0.0.

     redir can be run either from inetd or as a standalone daemon.  In –inetd mode the listening SRC:PORT combo is handled by another process, usually inetd, and a connected
     socket is handed over to redir via stdin.  Hence only [DST]:PORT is required in –inetd mode.  In standalone mode redir can run either in the foreground, -n, or in the back‐
     ground, detached like a proper UNIX daemon.  This is the default.  When running in the foreground log messages are also printed to stderr, unless the -s flag is given.

     Depending on how redir was compiled, not all options may be available.

 

+ Use redir to redirect TCP traffic one time

 

Lets say you have a MySQL running on remote machine on some internal or external IP address, lets say 192.168.0.200 and you want to redirect all traffic from remote host to the machine (192.168.0.50), where you run your Apache Webserver, which you want to configure to use
as MySQL localhost TCP port 3306.

Assuming there are no irewall restrictions between Host A (192.168.0.50) and Host B (192.168.0.200) is already permitting connectivity on TCP/IP port 3306 between the two machines.

To open redirection from localhost on 192.168.0.50 -> 192.168.0.200:

 

server:~# redir –laddr=127.0.0.1 –lport=3306 –caddr=192.168.0.200 –cport=3306

 

If you need other third party hosts to be additionally reaching 192.168.0.200 via 192.168.0.50 TCP 3306.

root@server:~# redir –laddr=192.168.0.50 –lport=3306 –caddr=192.168.0.200 –cport=3306


Of course once you close, the /dev/tty or /dev/vty console the connection redirect will be cancelled.

 

+ Making TCP port forwarding from Host A to Host B permanent


One solution to make the redir setup rules permanent is to use –rinetd option or simply background the process, nevertheless I prefer to use instead GNU Screen.
If you don't know screen is a vVrtual Console Emulation manager with VT100/ANSI terminal emulation to so, if you don't have screen present on the host install it with whatever Linux OS package manager is present and run:

 

root@server:~#screen -dm bash -c 'redir –laddr=127.0.0.1 –lport=3306 –caddr=192.168.0.200 –cport=3306'

 

That would run it into screen session and detach so you can later connect, if you want you can make redir to also log connections via syslog with ( -s) option.

I found also useful to be able to track real time what's going on currently with the opened redirect socket by changing redir log level.

Accepted log level is:

 

  -l, –loglevel=LEVEL
             Set log level: none, err, notice, info, debug.  Default is notice.

 

root@server:/ # screen -dm bash -c 'redir –laddr=127.0.0.1 –lport=3308 –caddr=192.168.0.200 –cport=3306 -l debug'

 

To test connectivity works as expected use telnet:
 

root@server:/ # telnet localhost 3308
Trying 127.0.0.1…
Connected to localhost.
Escape character is '^]'.
g
5.5.5-10.3.29-MariaDB-0+deb10u1-log�+c2nWG>B���o+#ly=bT^]79mysql_native_password

6#HY000Proxy header is not accepted from 192.168.0.19 Connection closed by foreign host.

once you attach to screen session with

 

root@server:/home #  screen -r

 

You will get connectivity attempt from localhost logged : .
 

redir[10640]: listening on 127.0.0.1:3306
redir[10640]: target is 192.168.0.200:3306
redir[10640]: Waiting for client to connect on server socket …
redir[10640]: target is 192.168.0.200:3306
redir[10640]: Waiting for client to connect on server socket …
redir[10793]: peer IP is 127.0.0.1
redir[10793]: peer socket is 25592
redir[10793]: target IP address is 192.168.0.200
redir[10793]: target port is 3306
redir[10793]: Connecting 127.0.0.1:25592 to 127.0.0.1:3306
redir[10793]: Entering copyloop() – timeout is 0
redir[10793]: Disconnect after 1 sec, 165 bytes in, 4 bytes out

The downsides of using redir is redirection is handled by the separate process which is all time hanging in the process list, as well as the connection redirection speed of incoming connections might be about at least 30% slower to if you simply use a software (firewall ) redirect such as iptables. If you use something like kernel IP set ( ipsets ). If you hear of ipset for a first time and you wander whta it is below is short package description.

 

root@server:/root# apt-cache show ipset|grep -i description -A13 -B5
Maintainer: Debian Netfilter Packaging Team <pkg-netfilter-team@lists.alioth.debian.org>
Architecture: amd64
Provides: ipset-6.38
Depends: iptables, libc6 (>= 2.4), libipset11 (>= 6.38-1~)
Breaks: xtables-addons-common (<< 1.41~)
Description-en: administration tool for kernel IP sets
 IP sets are a framework inside the Linux 2.4.x and 2.6.x kernel which can be
 administered by the ipset(8) utility. Depending on the type, currently an
 IP set may store IP addresses, (TCP/UDP) port numbers or IP addresses with
 MAC addresses in a  way which ensures lightning speed when matching an
 entry against a set.
 .
 If you want to
 .
  * store multiple IP addresses or port numbers and match against the
    entire collection using a single iptables rule.
  * dynamically update iptables rules against IP addresses or ports without
    performance penalty.
  * express complex IP address and ports based rulesets with a single
    iptables rule and benefit from the speed of IP sets.

 .
 then IP sets may be the proper tool for you.
Description-md5: d87e199641d9d6fbb0e52a65cf412bde
Homepage: http://ipset.netfilter.org/
Tag: implemented-in::c, role::program
Section: net
Priority: optional
Filename: pool/main/i/ipset/ipset_6.38-1.2_amd64.deb
Size: 50684
MD5sum: 095760c5db23552a9ae180bd58bc8efb
SHA256: 2e2d1c3d494fe32755324bf040ffcb614cf180327736c22168b4ddf51d462522

Howto create Linux Music Audio CD from MP3 files / Create playable WAV format Audio CD Albums from MP3s

Tuesday, July 16th, 2019

cdburning-audio-music-cd-from-mp3-on-linuxcomapct-disc-tux-linux-logo

Recently my Mother asked me to prepare a Music Audio CD for her from a popular musician accordionist Stefan Georgiev from Dobrudja who has a unique folklore Bulgarian music.

As some of older people who still remember the age of the CD and who had most likely been into the CD burning Copy / Piracy business so popular in the countries of the ex-USSR so popular in the years 1995-2000 audio ,  Old CD Player Devices were not able to play the MP3 file format due to missing codecs (as MP3 was a proprietary compression that can't be installed on every device without paying the patent to the MP3 compression rights holder.

The revolutionary MP3 compression used to be booming standard for transferring Music data due to its high compression which made an ordinary MP3 of 5 minutes of 5MB (10+ times more compression than an ordinary classic WAV Audio the CPU intensiveness of MP3 files that puts on the reading device, requiring the CD Player to have a more powerful CPU.

Hence  due to high licensing cost and requirement for more powerful CPU enabled Audio Player many procuders of Audio Players never introduced MP3 to their devices and MP3 Neve become a standard for the Audio CD that was the standard for music listening inside almost every car out there.

Nowdays it is very rare need to create a Audio CD as audio CDs seems to be almost dead (As I heard from a Richard Stallman lecture In USA nowadays there is only 1 shop in the country where you can still buy CD or DVD drives) and only in third world as Africa Audio CDs perhaps are still in circulation.

Nomatter that as we have an old Stereo CD player on my village and perhaps many others, still have some old retired CD reading devices being able to burn out a CD is a useful thing.

Thus to make mother happy and as a learning excercise, I decided to prepare the CD for her on my Linux notebook.
Here I'll shortly describe the takes I took to make it happen which hopefully will be useful for other people that need to Convert and burn Audio CD from MP3 Album.

 

1. First I downloaded the Album in Mp3 format from Torrent tracker

My homeland Bulgaria and specific birth place place the city of Dobrich has been famous its folklore:  Galina Durmushlijska and Stefan Georgiev are just 2 of the many names along with Оркестър Кристал (Orchestra Crystal) and the multitude of gifted singers. My mother has a santiment for Stefan Georgiev, as she listened to this gifted accordinist on her Uncle's marriage.

Thus In my case this was (Стефан Георгиев Хора и ръченици от Добруджа) the album full song list here If you're interested to listen the Album and Enjoy unique Folklore from Dobrudja (Dobrich) my home city, Stefan Georgiev's album Hora and Rachenica Dances is available here

 


Stefan_Georgiev-old-audio-Music-CD-Hora-i-Rychenici-ot-Dobrudja-Horos-and-Ruchenitsas-from-Dobrudja-CD_Cover
I've downloaded them from Bulgarian famous torrent tracker zamunda.net in MP3 format.
Of course you need to have a CD / DVD readed and write device on the PC which nowdays is not present on most modern notebooks and PCs but as a last resort you can buy some cheap External Optical CD / DVD drive for 25 to 30$ from Amazon / Ebay etc.

 

2. You will need to install a couple of programs on Linux host (if you don't have it already)


To be able to convert from command line from MP3 to WAV you will need as minimum ffmpeg and normalize-audio packages as well as some kind of command line burning tool like cdrskin  wodim which is
the fork of old good known cdrecord, so in case if you you're wondering what happened with it just
use instead wodim.

Below is a good list of tools (assuming you have enough HDD space) to install:

 

root@jeremiah:/ # apt-get install –yes dvd+rw-tools cdw cdrdao audiotools growisofs cdlabelgen dvd+rw-tools k3b brasero wodim ffmpeg lame normalize-audio libavcodec58

 

Note that some of above packages I've installed just for other Write / Read operations for DVD drives and you might not need that but it is good to have it as some day in future you will perhaps need to write out a DVD or something.
Also the k3b here is specific to KDE and if you're a GNOME user you could use Native GNOME Desktop app such brasero or if you're in a more minimalistic Linux desktop due to hardware contrains use XFCE's native xfburn program.

If you're a console / terminal geek like me you will definitely enjoy to use cdw
 

root@jeremiah:/ # apt-cache show cdw|grep -i description -A 1
Description-en: Tool for burning CD's – console version
 Ncurses-based frontend for wodim and genisoimage. It can handle audio and

Description-md5: 77dacb1e6c00dada63762b78b9a605d5
Homepage: http://cdw.sourceforge.net/

 

3. Selecting preferred CD / DVD / BD program to use to write out the CD from Linux console


cdw uses wodim (which is a successor of good old known console cdrecord command most of use used on Linux in the past to burn out new Redhat / Debian / different Linux OS distro versions for upgrade purposes on Desktop and Server machines.

To check whether your CD / DVD drive is detected and ready to burn on your old PC issue:

 

root@jeremiah:/# wodim -checkdrive
Device was not specified. Trying to find an appropriate drive…
Detected CD-R drive: /dev/cdrw
Using /dev/cdrom of unknown capabilities
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : 'HL-DT-ST'
Identification : 'DVDRAM GT50N    '
Revision       : 'LT20'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R

You can also use xorriso (whose added value compared to other console burn cd tools is is not using external program for ISO9660 formatting neither it use an external or an external burn program for CD, DVD or BD (Blue Ray) drive but it has its own libraries incorporated from libburnia-project.org libs.

Below output is from my Thinkpad T420 notebook. If the old computer CD drive is there and still functional in most cases you should not get issues to detect it.

cdw ncurses text based CD burner tool's interface is super intuitive as you can see from below screenshot:

cdw-burn-cds-from-console-terminal-on-GNU-Linux-and-FreeBSD-old-PC-computer

CDW has many advanced abilities such as “blanking” a disk or ripping an audio CD on a selected folder. To overcome the possible problem of CDW not automatically detecting the disk you have inserted you can go to the “Configuration” menu, press F5 to enter the Hardware options and then on the first entry press enter and choose your device (by pressing enter again). Save the setting with F9.
 

4. Convert MP3 / MP4 Files or whatever format to .WAV to be ready to burn to CD


Collect all the files you want to have collected from the CD album in .MP3 a certain directory and use a small one liner loop to convert files to WAV with ffmpeg:
 

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

for i in $( ls *.mp3); do ffmpeg -i $i $i.wav; done


If you don't have ffmpeg installed and have mpg123 you can also do the Mp3 to WAV conversion with mpg123 cmd like so:

 

for i in $( ls ); do mpg123 -w $i.wav $i.mp3; done


Another alternative for conversion is to use good old lame (used to create Mp3 audio files but abling to also) decode
mp3 to wav.

 

lame –decode somefile.mp3 somefile.wav


In the past there was a burn command tool that was able to easily convert MP3s to WAV but in up2date Linux modern releases it is no longer available most likely due to licensing issues, for those on older Debian Linux 7 / 8 / 9 / Ubuntu 8 to 12.XX / old Fedoras etc. if you have the command you can install burn and use it (and not bother with shell loops):

apt-get install burn

or

yum install burn


Once you have it to convert

 

$ burn -A -a *.mp3
 

 

5. Fix file naming to remove empty spaces such as " " and substitute to underscores as some Old CD Players are
unable to understand spaces in file naming with another short loop.

 

for f in *; do mv "$f" `echo $f | tr ' ' '_'`; done

 

6. Normalize audio produced .WAV files (set the music volume to a certain level)


In case if wondering why normalize audio is needed here is short extract from normalize-audio man page command description to shed some light.

"normalize-audio  is  used  to  adjust  the volume of WAV or MP3 audio files to a standard volume level.  This is useful for things like creating mp3 mixes, where different recording levels on different albums can cause the volume to  vary  greatly from song to song."
 

cd /disk/Music/Mp3s/Singer-Album-directory-with-MP3/

normalize-audio -m *.wav

 

7. Burn the produced normalized Audio WAV files to the the CD

 

wodim -v -fix -eject dev='/dev/sr0' -audio -pad *.wav


Alternatively you can conver all your MP3 files to .WAV with anything be it audacity
or another program or even use 
GNOME's CDBurn tool brasero (if gnome user) or KDE's CDBurn which in my opinion is
the best CD / DVD burning application for Linux K3B.

Burning Audio CD with K3b is up to few clicks and super easy and even k3b is going to handle the MP3 to WAV file Conversion itself. To burn audio with K3B just run it and click over 'New Audio CD Project'.

k3b-on-debian-gnu-linux-burn-audio-cd-screenshot

For those who want to learn a bit more on CD / DVD / Blue-Ray burning on GNU / Linux good readings are:
Linux CD Burning Mini Howto, is Linux's CD Writing Howto on ibiblio (though a bit obsolete) or Debian's official documentation on BurnCD.
 

8. What we learned here


Though the accent of this tutorial was how to Create Audio Music CD from MP3 on GNU / Linux, the same commands are available in most FreeBSD / NetBSD / OpenBSD ports tree so you can use the same method to build prepare Audio Music CD on *BSDs.

In this article, we went through few basic ways on how to prepare WAV files from MP3 normalize the new created WAV files on Linux, to prepare files for creation of Audio Music CD for the old mom or grandma's player or even just for fun to rewind some memories. For GUI users this is easily done with  k3b,  brasero or xfburn.

I've pointed you to cdw a super useful text ncurses tool that makes CD Burninng from plain text console (on servers) without a Xorg / WayLand  GUI installed super easy. It was shortly reviewed what has changed over the last few years and why and why cdrecord was substituted for wodim. A few examples were given on how to handle conversion through bash shell loops and you were pointed to some extra reading resources to learn a bit more on the topic.
There are plenty of custom scripts around for doing the same CD Burn / Covnersion tasks, so pointing me to any external / Shell / Perl scripts is mostly welcome.

Hope this learned you something new, Enjoy ! 🙂

Elder (Starets) Tadej Vitovishki explaining on the perpetual Grace of the Lord Jesus Christ and the Lord’s prayer importance for daily Christian living

Wednesday, March 18th, 2015

Elder (Starets) Tadej Vitovishki explaining on the perpetual Grace of the Lord Jesus Christ and the Lord's prayer importance for daily Christian living – http://s.www.pc-freak.net/url/323 Tateij Vitovnishki is among the few true spiritual enlightened people of our time who had achieved the gift of never ending prayer Lord Jesus Christ have mercy on me the sinner. It is interesting that the Elder advises us to not worry about events in our life or what will happen as God will order averything in our life for our best. So the standard way of thinking we have that we need to work hard to buy apartments and cars and the never ending lust for money is something that will never give us rest or drive us closer to God, that's why the Elder says he doesn't worry about anything but just concentrates on prayer and believes God will provide him with everything needed. Amazing Elder, let him pray for us the sinners!

 

Must have software on freshly installed windows – Essential Software after fresh Windows install

Friday, March 18th, 2016

Install-update-multiple-programs-applications-at-once-using-ninite

If you're into IT industry even if you don't like installing frequently Windows or you're completely Linux / BSD user, you will certainly have a lot of friends which will want help from you to re-install or fix their Windows 7 / 8 / 10 OS. At least this is the case with me every year, I'm kinda of obliged to install fresh windowses on new bought friends or relatives notebooks / desktop PCs.

Of course according to for whom the new Windows OS installed the preferrences of necessery software varies, however more or less there is sort of standard list of Windows Software which is used daily by most of Avarage Computer user, such as:
 

I tend to install on New Windows installs and thus I have more or less systematized the process.

I try to usually stick to free software where possible for each of the above categories as a Free Software enthusiast and luckily nowadays there is a lot of non-priprietary or at least free as in beer software available out there.

For Windows sysadmins or College and other public institutions networks including multiple of Windows Computers which are not inside a domain and also for people in computer repair shops where daily dozens of windows pre-installs or a set of software Automatic updates are  necessery make sure to take a look at Ninite

ninite-automate-windows-program-deploy-and-update-on-new-windows-os-openoffice-screenshot

As official website introduces Ninite:

Ninite – Install and Update All Your Programs at Once

Of course as Ninite is used by organizations as NASA, Harvard Medical School etc. it is likely the tool might reports your installed list of Windows software and various other Win PC statistical data to Ninite developers and most likely NSA, but this probably doesn't much matter as this is probably by the moment you choose to have installed a Windows OS on your PC.

ninite-choises-to-build-an-install-package-with-useful-essential-windows-software-screenshot
 

For Windows System Administrators managing small and middle sized network PCs that are not inside a Domain Controller, Ninite could definitely save hours and at cases even days of boring install and maintainance work. HP Enterprise or HP Inc. Employees or ex-employees would definitely love Ninite, because what Ninite does is pretty much like the well known HP Internal Tool PC COE.

Ninite could also prepare an installer containing multiple applications based on the choice on Ninite's website, so that's also a great thing especially if you need to deploy a different type of Users PCs (Scientific / Gamers / Working etc.)

Perhaps there are also other useful things to install on a new fresh Windows installations, if you're using something I'm missing let me know in comments.

How to Copy large data directories between 2 Linux / Unix servers without direct ssh / ftp access between server1 and server2 other by using SSH, TAR and Unix pipes

Monday, April 27th, 2015

how-to-copy-large-data-directories-between-2-linux-unix-servers-without-direct-ssh-ftp-access-btween-each-other

In a Web application data migration project, I've come across a situation where I have to copy / transfer 500 Gigabytes of data from Linux server 1 (host A) to Linux server 2 (host B). However the two machines doesn't have direct access to each other (via port 22) for security reasons and hence I cannot use sshfs to mount remotely host dir via ssh and copy files like local ones.

As this is a data migration project its however necessery to migrate the data finding a way … Normal way companies do it is to copy the data to External Hard disk storage and send it via some Country Post services or some employee being send in Data center to attach the SAN to new server where data is being migrated However in my case this was not possible so I had to do it different.

I have access to both servers as they're situated in the same Corporate DMZ network and I can thus access both UNIX machines via SSH.

Thanksfully there is a small SSH protocol + TAR archiver and default UNIX pipe's capabilities hack that makes possible to transfer easy multiple (large) files and directories. The only requirement to use this nice trick is to have SSH client installed on the middle host from which you can access via SSH protocol Server1 (from where data is migrated) and Server2 (where data will be migrated).

If the hopping / jump server from which you're allowed to have access to Linux  servers Server1 and Server2 is not Linux and you're missing the SSH client and don't have access on Win host to install anything on it just use portable mobaxterm (as it have Cygwin SSH client embedded )

Here is how:
 

jump-host:~$ ssh server1 "tar czf – /somedir/" | pv | ssh server2 "cd /somedir/; tar xf


As you can see from above command line example an SSH is made to server1  a tar is used to archive the directory / directories containing my hundred of gigabytes and then this is passed to another opened ssh session to server 2  via UNIX Pipe mechanism and then TAR archiver is used second time to unarchive previously passed archived content. pv command which is in the middle is not obligitory though it is a nice way to monitor status about data transfer like below:
 

500GB 0:00:01 [10,5MB/s] [===================================================>] 27%


P.S. If you don't have PV installed install it either with apt-get on Debian:

 

debian:~# apt-get install –yes pv

 

Or on CentOS / Fedora / RHEL etc.

 

[root@centos ~]# yum -y install pv

 

Below is a small chunk of PV manual to give you better idea of what it does:

NAME
       pv – monitor the progress of data through a pipe

SYNOPSIS
       pv [OPTION] [FILE]…
       pv [-h|-V]

DESCRIPTION
       pv  allows  a  user to see the progress of data through a pipeline, by giving information such as time elapsed, percentage
       completed (with progress bar), current throughput rate, total data transferred, and ETA.

       To use it, insert it in a pipeline between two processes, with the appropriate options.  Its standard input will be passed
       through to its standard output and progress will be shown on standard error.

       pv  will  copy  each  supplied FILE in turn to standard output (- means standard input), or if no FILEs are specified just
       standard input is copied. This is the same behaviour as cat(1).

       A simple example to watch how quickly a file is transferred using nc(1):

              pv file | nc -w 1 somewhere.com 3000

       A similar example, transferring a file from another process and passing the expected size to pv:

              cat file | pv -s 12345 | nc -w 1 somewhere.com 3000


Note that with too big file transfers using PV will delay data transfer because everything will have to pass through another 2 pipes, however for file transfers up to few gigabytes its really nice to include it.

If you only need to transfer huge .tar.gz archive and you don't bother about traffic security (i.e. don't care whether transferred traffic is going through encrypted SSH tunnel and don't want to put an overhead to both systems for encrypting the data and you have some unfiltered ports between host 1 and host 2 you can run netcat on host 2 to listen for connections and forward .tar.gz content via netcat's port like so:
 

linux2:~$ nc -l -p 12345 > /path/destinationfile
linux2:~$ cat /path/sourcfile | nc desti.nation.ip.address 12345


Another way to transfer large data without having connection with server1 and server2 but having connection to a third host PC is to use rsync and good old SSH Tunneling, like so:
 

jump-host:~$ ssh -R 2200:Linux-server1:22 root@Linux-server2 "rsync -e 'ssh -p 2200' –stats –progress -vaz /directory/to/copy root@localhost:/copy/destination/dir"

mod_rewrite redirect rule 80 to 443 on Apache webserver

Wednesday, April 2nd, 2014

A classic sysadmin scenario is to configure new Apache webserver with requirement to have an SSL ceriticate installed and working on port 443 and all requests coming on port 80 to be redirected to https://.
On Apache this is done with simple mod_rewrite rule:

RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}

Before applying the rule don't forget to have Apache mod_rewrite enabled usually it is not enabled on default most Linux distributions by default.
On shared hostings if you don't have access to directly modify Apache configuration but have .htaccess enabled you can add above rules also to .htaccess

Add this to respective VirtualHost configuration and restart Apache and that's it. If after configuring it for some reason it is not working debug mod_rewrite issues by enabling mod_rewrite's rewrite.log

Other useful Apache mod_rewrite redirect rule is redirect a single landing page from HTTP to HTTP

RewriteEngine On
RewriteRule ^apache-redirect-http-to-https.html$ https://www.site-url.com/apache-redirect-http-to-https.html [R=301,L]

!Note! that in case where performance is a key requirement for a website it might be better to use the standard way to redirect HTTP to HTTPS protocol in Apache through:

ServerName www.site-url.com Redirect / https://www.site-url.com/

To learn more on mod_rewrite redirecting  check out this official documentation on Apache's official site.

Windows equivalent of Linux which, whereis command – Windows WHERE command

Friday, June 6th, 2014

windows-find-commands-full-location-where-which-linux-commands-equivalent-in-windows-where-screenshot
In Linux there are the which and whereis commands showing you location of binaries included in $PATH # which lsof /usr/bin/lsof

# whereis lsof
lsof: /usr/bin/lsof /usr/share/man/man8/lsof.8.gz

so question arises what is which / whereis command Linux commands Windows equivalent?

In older Windows Home / Server editions – e.g. – Windows XP, 2000, 2003 – there is no standard installed tool to show you location of windows %PATH% defined executables. However it is possible to add the WHERE command binary by installing Resource Kit tools for administrative tasks.

windows-resource-kit-tools-install-where-linux-command-equivalent-in-windows

 

In Windows Vista / 7 / 8 (and presumably in future Windows releases), WHERE command is (will be) available by default

C:\Users\Georgi>WHERE SQLPLUS
D:\webdienste\application\oracle\11.2.0\client_1\BIN\sqlplus.exe

Cheers! 🙂

My struggles to find good substitute for old QWERTY Nokia 9300 Communicator and The Death of QWERTY Smart phones

Monday, January 27th, 2014

Nowadays having a a touch screen mobile phone has become like a standard. I'm not such a big fan of Touch screen technology, thus I've been fighting with the idea to own a touch screen phone for a year or so. Just till recently I happily lived with my old Nokia 9300i with a physical QWERTY keyboard for already 4 years.

Unfortunately lately while talking with my Nokia I started getting frequent voice interruptions missing words in my phone call conversations and need to ask person I'm talking to, to repeat his words / sentence in order to understand what is communicated .. I'm economic person and therefore don't like bying anything new if it is not absolutely necessary so I opened the phone and clean it hoping that this will solve the conversation issues but with no luck. With this half-usable mobile my only option left was to buy a new mobile phone.

I'm not very rigorious on what a mobile phone should be and I'm very much minimalist by heart so I was thinking of bying new cheapest available Nokia phone on the market and solve my "issue" quick and efficient,  only problem was  I'm quite used already of using my handy QWERTY phone as a note taking device thus I preferred to not buy a keypad mobile phone but get again a smartphone with physical QWERTY.

I have consulted with some friends who are more knowledgable on what's latest on mobile phone market with a question what will be a good substitute for my Nokia Communicator 9300i and heard comments like:
'IPhone is the most functional and superior in interface', while some friends and colleagues adviced me:
'Choose an Android based phone as Android is Linux based and gives more freedom to the user as well as has more free applications to install'

I appreaciated my friends help but I didn't like the idea to buy a Smartphone with a touchscreen display – virtual keyboard is not so confortable as having a physical one and besides this is a very slow interface compared to physical keys. Thus initially strongly rejected the idea of bying a phone without a physical keyboard. After some weeks of pondering and checking in the market – in 3 Major mobile operators shops in Bulgaria MTel, Globul and VIVACOM and HANDY store. I've find out currently on the market there is no good price / quality and functionality ratio (qwerty keyboard mobile) available. My options were limited to either by a Nokia Asha 210 or some variance or a Blackberry mobile.

nokia_asha_210_mobile_phone

In first glimpse I liked the Nokia ASHA 210 – QWERTY powered mobile  but after noticing the blue Facebook "F" button got quickly jolted.
The sales lady offered me a couple of other Nokias with Qwerty keyboard as well as a Blackberry 9320 Curve.

blackberry_curve_smart_mobile_phone
After a quick test of all QWERTY mobiles, found the intertface on both is so inferior to IPhone's IOS and Android based phones.
I asked my HP workmates for advice of a good QWERTY bundled mobile phone with Android and was referred to Motorolla Droid 3 – which seems to among the only options on the market for mobile Phone which have both Android Operating System and a Physical QWERTY keyboardMotorolla Droid 3 seemed to be exactly the mobile I was looking for but unfortunately it is not available in Mobile phones stores in Bulgaria and only in bulgaria is only offered for sale as a second hand and I had to buy it over the Internet (I prefer not to buy on the Internet). Even if I bought it as second hand  DROID 3's price is too high for my budget – 250 EUR!

Motorola-Droid-3-mobile-nokia-9300i-substitute

I wanted to buy economic phone and same time to have a good balance between price and phone modernity, same time don't tie myself with mobile operator yearly tax plan thus decided to pay my whole mobile price in cache (no credits, no binding 2 / 3 year conversation plans).

After evaluating the options on Market I stopped on two mobiles identical by price 150 EUR I could choose between Samsung Galaxy Trend Lite or ZTE Blade 3. The sales lady adviced me its better to get the ZTE Blade 3 than Samsung Galaxy Trend Lite (S7350) because ZTE has better Camera (5 Mpixels), a better Display and has much less hardware issues than Samsung Galaxy Lite.

Samsung-Galaxy-Trend-Lite-S7390-smart-mobile-phone

 

Finally I bought the ZTE Blade 3 and nowdays I'm trying to get used to it and to be honest even with a week passed I still can't get used to the Virtual Keyboard

Android interface is quite shiny but a little bit chaotic if compared to design use interface I've tested on IPhones. Android OS seems to behave very weird at times but in general is quite easy to use. Managing / installing / Removing applications from Google AppStore is done by only 2 clicks. My major concern on Android is its highly addictive. I've catch myself, since last week I spend much more time using my mobile than before with my Nokia Communicator …
ZTE-Blade-III-Black-smart-phone

To conclude it I would say living with a smartphone has its advantagous (you can easily check weather prognosis / news) and do a number of things with it, but it is addictive .. obviously its easy to  become an Android addict and spend your free time on useless stuff like installing / testing new apps and playing with phone. Having a smartphone just like I priorly suspected is a big time eater and it seems my hypothesis  that its better to live without a smart phone is true. But who knows, perhaps its just a moment addictiveness just like with any new thing posession – time will show. In meantime I believe my ZTE Blade III – purchase was a good deal as it gives me opportunity to explore Android OS. I'll stop here with my ranting and excuse myself if the article was too boring …Please drop me a comment with mobile types and names who had QWERTY keyboard and a modern OS. Very sadly it seems the QWERTY hardware keyboard mobiles will soon be dead and gone …

How to make SSH tunnel with PuTTY terminal client

Monday, November 18th, 2013

Create-how to make ssh tunnel with Putty on microsoft windows Vista / 7 XP / 2000
Earlier I blogged how to create SSH tunnels on Linux. Another interesting thing is how to make SSH tunnels on Windows. This can be done with multiple SSH clients but probably quickest and most standard way is to do create SSH tunnel with Putty. So why would one want to make SSH tunnel to a Windows host? Lets say your remote server has a port filtered to the Internet but available to a local network to which you don't have direct access, the only way to access the port in question then is to create SSH tunnel between your computer and remote machine on some locally binded port (lets say you need to access port 80 on remote host and you will access it through localhost tunneled through 8080). Very common scenario where tunneling comes handy if you have a Tomcat server behind firewalled DMZ| / load balancer or Reverse Proxy. Usually on well secured networks direct access to Tomcat application server will be disabled to its listen port (lets say 11444). Another important great think of SSH tunnels is all information between Remote server and local PC are transferred in strong SSH crypted form so this adds extra security level to your communication.
Once "real life" case of SSH tunnel is whether you have to deploy an application which fails after deployment with no meaningful message but error is returned by Apache Reverse Proxy. To test directly tomcat best thing is to create SSH tunnel between remote host 11444 and local host through 11444 (or any other port of choice). Other useful case would be if you have to access directly via CLI interface an SQL server lets say MySQL (remote port 3306 filtered) and inaccessible with mysql cli or Oracle DB with Db listener on port 1521 (needed to accessed via sqlplus).

In that case Putty's Tunneling capabilities comes handy especially if you don't have a Linux box at hand.
To create new SSH tunnel in putty to MySQL port 3306 on localhost (3306) – be sure MySQL is not running on localhost 😉
Open Putty Navigate in left pane config bar to:

SSH -> Tunnels

Type in

Source Port

– port on which SSH tunnel will be binded on your Windows (localhost / 127.0.0.1) in this example case 3306.

Then for

Destination
– IP address or host of remote host with number of port to which SSH tunnel will be opened.

N.B. ! in order to make tunneling possible you will need to have opened access to SSH port of remote (Destination) host

make ssh tunnel on Microsoft Windows putty to remote filtered mysql shot

make ssh tunnels on Microsoft windows putty to remote filtered mysql 2 screenshot

open ssh tunnel via WINDOWS port 22 on microsoft windows 7 screenshot

Once click Open you will be prompted for username on remote host in my case to my local router 83.228.93.76. Once you login to remote host open command prompt and try to connect Windows Command prompt Start -> Run (cmd.exe) ;

C:\Users\\hipo> telnet localhost 3306

Connection should be succesful and you from there on assuming you have the MySQL cli version for windows installed you can use to login to remote SQL via SSH tunnel with;

C:\Users\\hipo> mysql -u root -h localhost -p

To later remove existing SSH Tunnel go again to SSH -> Tunnels press on SSH tunnel and choose Remove

Further you can craete multiple SSH tunnels for all services to remote host where access is needed. Important think to remember when creating multiple SSH connections is source port on localhost to remote machine should be unique