Posts Tagged ‘fedora linux’

How to yum Install Gnome GUI, Latest Guest Addition Tools, Google Chrome latest version and rdesktop / xfreerdp / remmina remote RDP VNC clients On CentOS 7 / 8

Wednesday, July 28th, 2021

centos7-logo

I've just reinstalled my CentOS 7 Virtual Machine since after I tried to migrate a .vdi Virtual Box image to the new company laptop using a copy of Virtualbox VM via Microsoft OneDrive was a failure.
Thus I have rebuild all my CentOS Linux programs preinstalled on the old Virtual Machines from scratch, I use this virtual machine for a very simple tasks, so basicly most imporant tools I use is a plain SSH and VNC and Remote Desktop clients just to be able to remotely connect to remote Home based server.


1.Install GNOME Graphical Environment from command line on CentOS 7 with yum and configure it to start GUI on next OS boot


I've used a minimal CentOS installation – ISO CentOS-7-x86_64-DVD-1908.iso and this brings up the OS with a text mode only as usually CentOS is used to roll on Servers and rarely and many times admins did not want to have GUI at all, however my case is different since I do like to use Graphical Environment as I use my CentOS for all kind of testing that can be later applied to a Production machines that doesn't have a GUI, hence to install GNOME on CentOS run below cmds:
 

[root@centos ~ ]# yum group list
Loaded plugins: fastestmirror
There is no installed groups file.
Maybe run: yum groups mark convert (see man yum)
Loading mirror speeds from cached hostfile
Available Environment Groups:
 Minimal Install
 Compute Node
 Infrastructure Server
 File and Print Server
 Basic Web Server
 Virtualization Host
 Server with GUI
 GNOME Desktop
 KDE Plasma Workspaces
 Development and Creative Workstation
Available Groups:
 Compatibility Libraries
 Console Internet Tools
 Development Tools
 Graphical Administration Tools
 Legacy UNIX Compatibility
 Scientific Support
 Security Tools
 Smart Card Support
 System Administration Tools
 System Management
Done


[root@centos ~ ]# yum groupinstall "GNOME Desktop" "Graphical Administration Tools" -y


Enable GUI to be automatically start on CentOS VM boot in systemd this is configured with the "targets" instead of the well known classical runlevels (the well known /etc/inittab) is now obsolete in newer Linux distros.

[root@centos ~ ]# ln -sf /lib/systemd/system/runlevel5.target /etc/systemd/system/default.target


2. Install Guest Additions Tools on CentOS


The most basic thing to do once I've had the CentOS Linux release 7.7.1908 (Core) rolled out on the VirtualBox is of course to enable Guest Additions Tools

First I had to install of course Guest Additions Tools to allow myself to have a copy paste in clip board via the Host Machine (Windows 10) and the Guest Machine.
To do I had to:

[root@centos ~ ]# yum install kernel-headers.x86_64 -y

[root@centos ~ ]# rpm -Uvh https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

[root@centos ~ ]#  yum install perl gcc dkms kernel-devel kernel-headers make bzip2

To check the required VBoxLinuxAdditions.run script kernel headers are at place:

[root@centos ~ ]# ls -l /usr/src/kernels/$(uname -r)


You should get a list of kernel header files

Then once I've done the Insert Guest Additions CD Image from the VirtualBox VM upper menu. I've had to mount and load the guest additions via the script:
 

[root@centos ~ ]# mkdir /mnt/cdrom
[root@centos ~ ]# mount /dev/cdrom /mnt/cdrom
[root@centos ~ ]# sh VBoxLinuxAdditions.run

After rebooting the Virtual Machine, I've used the full screen functionality to test and configured immediately Shared Clipboard and Drag and Drop to be both set to (Bidirectional) as well as configured a Shared folder to provide my Windows Desktop under /mnt/shared_folder (as read write) as I usually do to be able to easily copy files from the VM and to the Windows.

3. Install Google Chrome on the CentOS Virtual Machine with yum
 

Next I've installed the chrome browser that was pretty trivial it is up to fetching the required 32 or 64 bit latest chrome binary this is usually on URL:

[root@centos ~ ]# wget https://dl.google.com/linux/direct/google-chrome-stable_current_x86_64.rpm

and installing Google Chrome with superuser with command:

[root@centos ~ ]# yum install ./google-chrome-stable_current_*.rpm -y

 

Loaded plugins: fastestmirror, langpacks
Examining ./google-chrome-stable_current_x86_64.rpm: google-chrome-stable-92.0.4515.107-1.x86_64
Marking ./google-chrome-stable_current_x86_64.rpm to be installed
Resolving Dependencies
–> Running transaction check
—> Package google-chrome-stable.x86_64 0:92.0.4515.107-1 will be installed
–> Processing Dependency: liberation-fonts for package: google-chrome-stable-92.0.4515.107-1.x86_64
Loading mirror speeds from cached hostfile
 * base: mirror.digitalnova.at
 * epel: fedora.ipacct.com
 * extras: mirror.digitalnova.at
 * updates: mirror.digitalnova.at
–> Processing Dependency: libvulkan.so.1()(64bit) for package: google-chrome-stable-92.0.4515.107-1.x86_64
–> Running transaction check
—> Package liberation-fonts.noarch 1:1.07.2-16.el7 will be installed
–> Processing Dependency: liberation-narrow-fonts = 1:1.07.2-16.el7 for package: 1:liberation-fonts-1.07.2-16.el7.noarch
—> Package vulkan.x86_64 0:1.1.97.0-1.el7 will be installed
–> Processing Dependency: vulkan-filesystem = 1.1.97.0-1.el7 for package: vulkan-1.1.97.0-1.el7.x86_64
–> Running transaction check
—> Package liberation-narrow-fonts.noarch 1:1.07.2-16.el7 will be installed
—> Package vulkan-filesystem.noarch 0:1.1.97.0-1.el7 will be installed
–> Finished Dependency Resolution

Dependencies Resolved

================================================================================
 Package                 Arch   Version         Repository                 Size
================================================================================
Installing:
 google-chrome-stable    x86_64 92.0.4515.107-1 /google-chrome-stable_current_x86_64
                                                                          259 M
Installing for dependencies:
 liberation-fonts        noarch 1:1.07.2-16.el7 base                       13 k
 liberation-narrow-fonts noarch 1:1.07.2-16.el7 base                      202 k
 vulkan                  x86_64 1.1.97.0-1.el7  base                      3.6 M
 vulkan-filesystem       noarch 1.1.97.0-1.el7  base                      6.3 k

Transaction Summary
================================================================================
Install  1 Package (+4 Dependent packages)

Total size: 263 M
Total download size: 3.8 M
Installed size: 281 M
Is this ok [y/d/N]: y
Downloading packages:
(1/4): liberation-fonts-1.07.2-16.el7.noarch.rpm           |  13 kB   00:00     
(2/4): liberation-narrow-fonts-1.07.2-16.el7.noarch.rpm    | 202 kB   00:00     
(3/4): vulkan-filesystem-1.1.97.0-1.el7.noarch.rpm         | 6.3 kB   00:00     
(4/4): vulkan-1.1.97.0-1.el7.x86_64.rpm                    | 3.6 MB   00:00     
——————————————————————————–
Total                                              3.0 MB/s | 3.8 MB  00:01     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : vulkan-filesystem-1.1.97.0-1.el7.noarch                      1/5 
  Installing : vulkan-1.1.97.0-1.el7.x86_64                                 2/5 
  Installing : 1:liberation-narrow-fonts-1.07.2-16.el7.noarch               3/5 
  Installing : 1:liberation-fonts-1.07.2-16.el7.noarch                      4/5 
  Installing : google-chrome-stable-92.0.4515.107-1.x86_64                  5/5 
  Verifying  : vulkan-1.1.97.0-1.el7.x86_64                                 1/5 
  Verifying  : 1:liberation-narrow-fonts-1.07.2-16.el7.noarch               2/5 
  Verifying  : 1:liberation-fonts-1.07.2-16.el7.noarch                      3/5 
  Verifying  : google-chrome-stable-92.0.4515.107-1.x86_64                  4/5 
  Verifying  : vulkan-filesystem-1.1.97.0-1.el7.noarch                      5/5 

Installed:
  google-chrome-stable.x86_64 0:92.0.4515.107-1                                 

Dependency Installed:
  liberation-fonts.noarch 1:1.07.2-16.el7                                       
  liberation-narrow-fonts.noarch 1:1.07.2-16.el7                                
  vulkan.x86_64 0:1.1.97.0-1.el7                                                
  vulkan-filesystem.noarch 0:1.1.97.0-1.el7             


4. Install usable Windows VNC and remote desktop (RDP Client) for CentOS Linux


There is a plenty of clients to choice from if you need to have an RDP client for Linux, but perhaps the most useful ones I usually use are remmina / rdesktop and freerdp. Usually I use remmina on Debian Linux, but under the VM somehow I was not able to make remmina work in Full Screen mode while connected to remote Windows 7 VPS server, thus I've first tried xfreerdp (that comes from default CentOS repositories) and is open source alternative to rdesktop (which is non free distributed binary).
 

[root@centos ~ ]$ sudo yum -y install freerdp


The basic use is:

[hipo@centos ~ ]$ xfreerdp –toggle-fullscreen <remote-server-address>


Unfortunately I did not succeeded to make xfreerdp be able to show me remote desktop in FullScreen mode so had to use additional repository package called nux-dextop to have rdesktop at my disposal.

To install it had to run:

[root@centos ~ ]# rpm –import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro 
[root@centos ~ ]# rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-1.el7.nux.noarch.rpm    
[root@centos ~ ]# yum install rdesktop

To connect to the remote RDP host in Fullscreen with rdesktop :
 

rdesktop -f <remote-server-address>

windows-7-remote-desktop-screenshot-connected-with-rdesktop

As telnet is not installed by default and it is so useful to check ports

5. Install GNU Image Manipulation Program for better screnshotting and Graphic edits


I usually do install GIMP (GNU Image Manipulation Program) since this is my favourite tool to make screenshot on Linux as well as do some minor graphic edits whenever necessery. I warmly recommend gimp to anyone. If you don't have basic GIMP tool and you plan to be daily working a lot with Linux sooner or later some skills with the program will be of a major use even for the most advanced sysadmin 🙂

root@centos ~ ]# yum install -y gimp

 

6. Install useful administration tools for daily sysadmin work – telnet, nmap, iftop, htop, iotop, iptraf-ng, tcpdump

 

Having basic analys tools and remote communication port testing, DNS, resolving and connection, cpu, mem statistics I find mostly useful. 

[root@centos .ssh]# yum install telnet nmap iftop htop vnstat sysstat iptraf-ng bind-utils -y

 

 

7. Set Open Explorer and SHOW Desktop key binding shortcuts for GNOME (to make daily work easier)

 


Another useful I do use in my newly installed Virtual Machines is the key combination of Windows (button key) + E – to easily open the GNOME equivalent of Windows Explorer (Nautilus) and Windows (key) + D to hide the active selected Window and Show Desktop. This is configured pretty easy in GNOME through:
 

$ gnome-control-center

Keyboard (Section)

Perhaps there is other stuff I need to add on the freshly installed Operating System if I remember something else interesting

configure-home-folder-and-hide-all-normal-windows-gnome-key-binding-howto-screenshot

 

8. Install gnome-tweaks to tweak a bit the desktop icon positionsing and additional gnome-shell extras

[root@centos hipo]# yum install -y gnome-shell-extension-workspace-indicator.noarch gnome-shell-extension-workspace-indicator.noarch gnome-shell-extension-suspend-button.noarch gnome-shell-extension-refresh-wifi.noarch gnome-shell-extension-updates-dialog.noarch gnome-shell-extension-windowoverlay-icons.noarch gnome-shell-extension-places-menu.noarch gnome-shell-extension-drive-menu.noarch gnome-shell-extension-apps-menu.noarch gnome-shell-extension-auto-move-windows.noarch gnome-tweaks gnome-shell-extension-systemMonitor.noarch gnome-shell-extension-openweather.noarch gnome-shell-extension-user-theme.noarch gnome-shell-extension-topicons-plus.noarch


Next step is to use gnome-tweaks to set multiple custom preference stuff you like on the gnome 3.28 GUI 

 

gnome-tweak-tool1

gnome-tweak-tool2

gnome-tweak-tool3

9. Change ( Fix) timezone to correct time on the Virtual Machine

[root@localhost ~]# timedatectl 
      Local time: Fri 2021-07-30 12:20:51 CEST
  Universal time: Fri 2021-07-30 10:20:51 UTC
        RTC time: Fri 2021-07-30 10:20:48
       Time zone: Europe/Berlin (CEST, +0200)
     NTP enabled: yes
NTP synchronized: yes
 RTC in local TZ: no
      DST active: yes
 Last DST change: DST began at
                  Sun 2021-03-28 01:59:59 CET
                  Sun 2021-03-28 03:00:00 CEST
 Next DST change: DST ends (the clock jumps one hour backwards) at
                  Sun 2021-10-31 02:59:59 CEST
                  Sun 2021-10-31 02:00:00 CET

[root@localhost ~]# ls -l /etc/localtime
lrwxrwxrwx. 1 root root 35 Jul 29 14:03 /etc/localtime -> ../usr/share/zoneinfo/Europe/Berlin


To change to correct timezone, you need to find out the long name for the timezone you want to use. The timezone naming convention usually uses “Region/City” format.

To list all available time zones, you can either list the files in the /usr/share/zoneinfo directory or use the timedatectl command.

[root@centos ~]# timedatectl list-timezones|tail -n 10
Pacific/Pohnpei
Pacific/Port_Moresby
Pacific/Rarotonga
Pacific/Saipan
Pacific/Tahiti
Pacific/Tarawa
Pacific/Tongatapu
Pacific/Wake
Pacific/Wallis
UTC


As I'm situated in Sofia Bulgaria to set the correct timezone to UTC (Universal Time Clock)  + 2 Hrs, i've checked the correct Continent/Country like so:

[root@centos ~]# timedatectl list-timezones|grep -i Sofia
Europe/Sofia

Once I've my Capital / Country time location  identified to set to it:

[root@centos ~]# timedatectl set-timezone your_time_zone

 

10. Configure remote connection hostname SSH aliases via ssh config ( ~/.ssh/config)

 


I'm having separate Virtual Machines running on my OpenXen virtualization Hypervisor server at different ports which I remember by heart under different hostnames, this saves me time to always type on command line long commands such as:
 

 

 

#  ssh long-hostname -p Port_number

 to make accessibility to remote machines via a simple Hostname Aliases, that forwards to remote port (that gets forwarded via a Local Network configure Netwrork Address Translation), I use the .ssh/config nice Host / Hostname / User / Port directives like below samples:

[hipo@centos .ssh]$ cat config 
Host pcfreak
User root
Port 2248
HostName 83.228.93.76

Host freak
User root
Port 2249
HostName 213.91.190.233


Host pcfrxenweb
User root
Port 2251
Hostname 83.228.93.76

Host pcfrxen
User root
Port 2250
Hostname 213.91.190.233

Now to connect to pcfrxen for example I simply type:

ssh pcfrxen

type in the password to remote VM and I'm in 🙂

The same could be achieved also with Adding Custom Hostname IP Aliases via ~/.bashrc or iteration script as I've explained earlier that fakes like custom /etc/hosts, but I usuaully prefer to use .ssh/config instead like explained above.

Note that above steps should work also on RHEL / Fedora Linux with a minor modifications, as usually this two distros share the RPM package manager. If someone tries to follow the guide and have success on any of this distros please drop a comment with feedback.
 

A lightweight Email Client Graphical client for old computers with Linux (Claws)

Sunday, August 12th, 2018

claws-email-logo-best-email-leightweight-client-for-older-computer-configurations-with-linux.

If you happen to be system administrating an old computers with some 512 Megabytes of RAM or 1 Gigabyte of Memory with preinstalled some archaic version of GNU / Linux distro such as Slackware, Calderra Linux,  Debian / Ubuntu / Fedora etc. and there is suddenly need to use this PCs with a decent graphical email client for its existing GUI environment LXDE / XFCE / WindowMaker / Mate etc. then Mozilla Thunderbird

Definitely won't be the client of choice especially if you have to add 5 or 10 email accounts (with a few hundred of emails laying on the remote mail server) to be periodically fetched via POP3 or IMAP protocol.

Of course there is always the option to just use a simple Text Email clients such as Fetchmail, PINE or MUTT and unload the PCs memory and CPU with the simplistic text interface however as most people are totally unacquainted with Linux console or terminal, for most that won't be the option of choice.
 

  • So what is the best solution for a lightweight Graphical Email Client for Linux for Old Computers ?


!!! Say Hello to Sylpheed CLAWS EMail Desktop client !!!

Best-Email-client-for-old-computers-with-Linux-Sylpheed-Claws_1-screenshot-on-Window-Maker

 

 

linux:~# apt-cache show claws-mail|grep -i descrip -A 3 -B 1
Breaks: claws-mail-extra-plugins (<< 3.9.1-1)
Description-en: Fast, lightweight and user-friendly GTK+2 based email client
 Claws Mail is a powerful and full-featured mail client formerly called
 Sylpheed-Claws. It is also extensible using loadable plugins, which can
 provide support for additional features, like other storage formats,
 feed reader, calendar management, mail filtering, etc.

Description-md5: f9d9f85803d938ab3d5fbc85f90e263a
Multi-Arch: foreign
Homepage: http://www.claws-mail.org
Section: mail

 

A. Installing Claws Email on Debian Linux distribution
 

Assuming you need to install claws on Debian based Linux distributions;

 

debian:~# apt-get install –yes claws-mail

 


B. Installing Claws on Fedora Linux distribution

For older Fedora Linux:
 

[root@fedora ~:]# yum install claws-mail

 

On a newer Fedora Linux installations (for those who are already used to Claws and migrate to a newer computer with a fresh Fedora install)
 

[root@fedora ~:]# dhf install claws-mail

 

Note that newer versions of Fedora Linux the default yum package manager has been substituted for the newer and (said to be more) advanced dhf
 

C. Installing Claws email on Slackware Linux

Claws Mail is also available as a (Tar XZ – That's a slackware highly compressed .tar.gz equivallent which saves a lot of space for its packages), to install on slack get the package from the CD / DVD or download from internet and:

 

darkstar:~# installpkg claws-mail*.txz

 


By the way Claws mail might be also the email client of choice (for those who don't have to be bound by the slavery of Office 365 / Microsoft Office and transporters and Active Domain Controller Directory with Outlook Express.

windows_claws-email-lightweight-email-client-screenshot

Even on old Computers with Microsoft Windows Claws email (which has also a Windows 32 Bit Port) might be among the best options for those who value their computer resources and interface simplicity and hence want to save memory and CPU load.

That is it,  try and enjoy Sylpheed Claws !

 

Disable Bluetooth on CentOS / RHEL (Redhat) / Fedora Linux servers – Disable hidd bluetooth devices

Thursday, January 29th, 2015

Disable_Bluetooth_on_CentOS_RHEL_Redhat_Fedora_Linux_servers_-_Disable_hidd_bluetooth_devices-logo

Bluetooth protocol on Linux is nice to have (supported) on Linux Desktop systems to allow easy communication wth PDAs, Tablets, Mobiles, Digital Cameras etc, However many newly purchased dedicated servers comes with Bluetooth support enabled which is a service rarely used, thus it is a good strong server security / sysadmin practice to remove the service supporting Blueetooth (Input Devices) on Linux hosts this is the hidd (daemon) service, besides that there are few Linux kernel modules to enable bluetooth support and removing it is also a very recommended practice while configuring new Production servers. 

Leaving Blueetooth enabled on Linux just takes up memory space and  potentially is a exposing server to possible security risk (might be hacked) remotely. 
Thus eearlier I've blogged on how bluetooth is disabled on Debian / Ubuntu Linux servers an optimization tuning (check) I do on every new server I have to configure, since administrating both RPM and Deb Linux distributions I usually also remove bluetooth hidd service support on every CentOS / RHEL / Fedora Linux – redhat  (where it is installed), here is how :

 

1. Disable Bluetooth in CentOS / RHEL Linux


a) First check whether hidd service is running on server:
 

[root@centos ~]# ps aux |grep -i hid
… 


b) Disable bluetooth services
 

[root@centos ~]# /etc/init.d/hidd stop
[root@centos ~]# chkconfig hidd off
[root@centos ~]# chkconfig bluetooth off
[root@centos ~]# /etc/init.d/bluetooth off


c) Disable any left Bluetooth kernel module (drivers), not to load on next server boot
 

[root@centos ~]# echo 'alias net-pf-31 off' >> /etc/modprobe.conf


If you don't need or intend to use in future server USBs it is also a good idea to disable USBs as well:
 

[root@centos ~]# lsmod|grep -i hid
usbhid                 33292  0
hid                    63257  1 usbhid
usbcore               123122  4 usb_storage,usbhid,ehci_hcd


[root@centos ~]# echo 'usbhid' >> /etc/modprobe.d/blacklist.conf
[root@centos ~]# echo 'hid' >> /etc/modprobe.d/blacklist.conf
[root@centos ~]# echo 'usbcore' >> /etc/modprobe.d/blacklist.conf

 

2. Disable Bluetooth on Fedora Linux

Execute following:
 

[hipo@fedora ~]# /usr/bin/sudo systemctl stop bluetooth.service
[hipo@fedora ~]# /usr/bin/sudo systemctl disable bluetooth.service

 
3. Disable Bluetooth on Gentoo / Slackware and other Linuces

An alternative way to disable bluetooth that should work across all Linux distributions / versions is:
 

[root@fedora ~]# su -c 'yum install rfkill'
[root@fedora ~]# su -c 'vi /etc/rc.d/rc.local'


Place inside, something like (be careful not to overwrite something, already execution on boot):
 

#!/bin/sh
rfkill block bluetooth
exit 0


4. Disable any other unnecessery loaded service on boot time

It is a good idea to also a good idea to check out your server running daemons, as thoroughfully as possible and remove any other daemons / kernel modules not being used by server.

To disable all unrequired services, It is useful to get a list of all enabled services, on RedHat based server issue:

 

[root@cento ~]#  chkconfig –list |grep "3:on" |awk '{print $1}'


 A common list of services you might want to disable if you're configuring (Linux, Apache, MySQL, PHP = LAMP) like server is:
 

chkconfig anacron off
chkconfig apmd off
chkconfig atd off
chkconfig autofs off
chkconfig cpuspeed off
chkconfig cups off
chkconfig cups-config-daemon off
chkconfig gpm off
chkconfig isdn off
chkconfig netfs off
chkconfig nfslock off
chkconfig openibd off
chkconfig pcmcia off
chkconfig portmap off
chkconfig rawdevices off
chkconfig readahead_early off
chkconfig rpcgssd off
chkconfig rpcidmapd off
chkconfig smartd off
chkconfig xfs off
chkconfig ip6tables off
chkconfig avahi-daemon off
chkconfig firstboot off
chkconfig yum-updatesd off
chkconfig mcstrans off
chkconfig pcscd off
chkconfig bluetooth off
chkconfig hidd off


In most cases you can just run script like this – centos-disable_non-required_essential_services_for_lamp_server.sh.
 

Another useful check the amount of services each of the running server daemons is using, here is how:
 

ps aux | awk '{print $4"t"$11}' | sort | uniq -c | awk '{print $2" "$1" "$3}' | sort -nr


Output of memory consumption check command is here

Quick way to access remotely your GNU / Linux Desktop – Access Linux Desktop from Mac and Windows 7

Tuesday, August 5th, 2014

how-to-access-linux-host-from-microsoft-windows-or-mac-client-xrdp-tightvnc-native-way-logo
For M$ Windows users its always handy to have remote access to your home PC or notebook via Remote Desktop (RDP) protocol.

However in GNU / Linux, there is no native implementation of RDP protocol. So if you're using Linux as your Desktop like me you will probably want to be able to access the Linux system remotely not only via terminal with SSH using (Putty) or MobaXTerm all in one tabbed Windows terminal program but also be able to use your Linux GNOME / KDE Graphical environment from anywhere on the Internet.

This will make you ponder – Is it possible to access Linux Desktop via proprietary RDP protocol and if not how you can achieve remote GUI access to Linux?

1. Using Linux Xorg and Xming Xserver for Windows

Most people should already know of Linux ability to start multiple Xserver sessions remotely which is the native way to access between two Linux hosts or access remotely Linux from other Linux UNIX like OS. It is also possible to use xinit / startx / xhost commands to establish remotely connection to new or running Linux (Xorg) Xserver by using them in combination with XMing – XServer for Windows running on the Windows host and Debian package (x11-xserver-utils) – providing xhost cmd, however this method is a bit complicated and not so convenient.

I used to be using this method XMing (whose mirror is here), earlier in my university years to use remotely my Debian Linux from  Windows 98 and this works perfectly fine.

2. Using RDP emulation with XRDP server

in order to be able to access your desk from any friend or computer club in the world using standard available in MS Windows Remote Desktop client (mstsc.exe).
There is also another alternative way by using Windows Desktop sharing RDP experimental server xrdp:
 

apt-cache show xrdp |grep -i descr -A 3
Description: Remote Desktop Protocol (RDP) server
 Based on research work by the rdesktop project, xrdp uses the Remote
 Desktop Protocol to present a graphical login to a remote client.
 xrdp can connect to a VNC server or another RDP server.

To make your Linux host accessible via RDP:

On Debian / Ubuntu etc. deb based Linux:

 

apt-get update
apt-get install xrdp

 
$ /etc/init.d/xrdp status
Checking status of Remote Desktop Protocol server xrdp                                             [ OK ]
Checking status of RDP Session Manager sesman

/etc/init.d/xrdp start

On  Fedora Linux:
 

yum -y install xrdp
systemctl enable xrdp.service
systemctl start xrdp.service
systemctl enable xrdp-sesman.service
systemctl start xrdp-sesman.service


It is possible to access remote Linux host using xrdp RDP server, but this will only work in older releases of mstsc.exe (Windows XP / Vista / 2003) and will not work on Windows 7 / 8, because in MS Windows 7 and onwards RDP proto version has changed and the client no longer has compatability with older mstsc releases. There is a work around for this for anyone who stubbornly want to use RDP protocol to access Linux host. If you want to connect to xrdp from Windows 7 you have to copy the old RDP client (mstsc.exe and mstscax.dll) from a WinXP install to the Windows 7 box and run it independently, from the default installed ones, anyways this method is time consuming and not really worthy …

3. Using the VNC withTightVNC server / client

 

Taking above in consideration, for me personally best way to access Linux host from Windows and Mac is to use simply the good old VNC protocol with TightVNC.

TightVNC is cross-platform free and open source remote Desktop client it uses RFB protocol to control another computer screen remotely.

To use tightvnc to access remote Debian / Ubuntu – deb based Linux screen, tightvncserver package has to be installed:

apt-cache show tightvncserver|grep -i desc -A 7
Description-en: virtual network computing server software
 VNC stands for Virtual Network Computing. It is, in essence, a remote
 display system which allows you to view a computing `desktop' environment
 not only on the machine where it is running, but from anywhere on the
 Internet and from a wide variety of machine architectures.

 .
 This package provides a server to which X clients can connect and the
 server generates a display that can be viewed with a vncviewer.

 

apt-get –yes install tightvncserver


TightVNCserver package is also available in default repositories of Fedora / CentOS / RHEL and most other RPM based distros, to install there:
 

yum -y install tightvnc-server


Once it is installed to make tightvncserver running you have to start it (preferrably with non-root user), usually this is the user with which you're using the system:

tightvncserver

You will require a password to access your desktops.

Password:
Verify:   
Would you like to enter a view-only password (y/n)? n

New 'X' desktop is rublev:4

Creating default startup script /home/hipo/.vnc/xstartup
Starting applications specified in /home/hipo/.vnc/xstartup
Log file is /home/hipo/.vnc/rublev:4.log

 

tightvncserver-running-in-gnome-terminal-debian-gnu-linux-wheezy-screenshot

To access now TightVncserver on the Linux host Download and Install TightVNC Viewer client

note that you need to download TightVNC Java Viewer JAR in ZIP archive – don't install 32 / 64 bit installer for Windows, as this will install and setup TightVNCServer on your Windows – and you probably don't want that (and – yes you will need to have Oracle Java VM installed) …
 

tightvnc-viewer-java-client-running-on-microsoft-windows-7-screenshot

Once unzipped run tightvnc-jviewer.jar and type in the IP address of remote Linux host and screen, where TightVNC is listening, as you can see in prior screenshot my screen is :4, because I run tightvnc to listen for connections in multiple X sessions. once you're connected you will be prompted for password, asker earlier when you run  tightvncserver cmd on Linux host.

If you happen to be on a Windows PC without Java installed or Java use is prohibited you can use TightVNC Viewer Portable Binary (mirrored here)

/images/tightvnc-viewer-portable-windows-7-desktop-screenshot

If you have troubles with connection, on Linux host check the exact port on which TightVncServer is running:
 

ps ax |grep -i Tightvnc

 8630 pts/8    S      0:02 Xtightvnc :4 -desktop X -auth /var/run/gdm3/auth-for-hipo-7dpscj/database -geometry 1024×768 -depth 24 -rfbwait 120000 -rfbauth /home/hipo/.vnc/passwd -rfbport 5904 -fp /usr/share/fonts/X11/misc/,/usr/share/fonts/X11/Type1/,/usr/share/fonts/X11/75dpi/,/usr/share/fonts/X11/100dpi/ -co /etc/X11/rgb

Then to check, whether the machine you're trying to connect from doesn't have firewall rules preventing the connection use (telnet) – if installed on the Windows host:
 

telnet www.pc-ferak.net 5904
Trying 192.168.56.101…
Connected to 192.168.56.101.
Escape character is '^]'.
RFB 003.008

telnet> quit
Connection closed.

remote-connection-via-tightvnc-to-linux-host-from-windows-7-using-tightvnc-java-client-screenshot
 

yum add proxy on CentOS, RHEL, Fedora Linux howto

Thursday, June 5th, 2014

yum-via-proxy-yum-package-management-mascot
Whether you had to install a CentOS server in a DMZ-ed network with paranoic system firewall rules or simply you want to use your own created RPM local repository to run RPM installs and CentOS system updates via monitored Proxy you will have to configure yum to use a proxy.

There is a standard way to do it by adding a proxy directive to /etc/yum.conf as explained in CentOS official documetnation.
However for some reason:

proxy=http://your-proxy-url.com:8080
proxy_username=yum-user
proxy_password=qwerty

proxy vars adding to /etc/yum.conf [main] section is not working on CentOS 6.5?
However there is a dirty patch by using the OS environment standard variable http_proxy
To make yum work via proxy in gnome-terminal run first:

export http_proxy=http://your-proxy-server.com:8080

or if proxy is protected by username / password run instead:

export username='yum-user'
export password='qwerty'
export http_proxy="http://$username:$password@your-proxy-server:8080/

Afterwards yum will work via the proxy, i.e.:

yum update && yum upgrade

To make http_proxy exported system wide check my previous post – Set Proxy System-Wide

Hope this helps someone.

How to disable GNOME popup notification in Debian Wheezy Linux

Friday, August 2nd, 2013

how to disable remove GNOME 2 / 3 popup e mail notification  Debian Ubuntu Linux screenshot

I found it very annoying to have a pop-up notification every time I receive a new email it is just pointless there especially, when I already use Thunderbird (IceDove) to fetch my email via pop3. This pop-up notification though planned to be useful messes with my Desktop and breaks the habit on how I'm used to old GNOME interface…. I remember same popup notification was present on older Fedora releases (back in time when I used Fedora Linux for my Desktop).

disable Gnome popup notification new email Debian GNU Linux Wheezy 7 screenshot

My logical guess was in order to disable popup notification in GNOME 3 I had to tamper with gconf-editor. In gconf-editor config database there is:

Apps -> Notification daemon

Problem it is not possible to turn it off. Only available change options are:

default-sound, popup_location, sound_enabled, and theme

After some time of try / fail attempts I found the solution on linuxquestions forum, its quite raw solution but it works, all I had to do is change permissions of /usr/lib/notification-daemon/notification-daemon;

debian:~# chmod 0000 /usr/lib/notification-daemon/notification-daemon

Another thing that is handy to disable is POP UP Window with warning that you have low disk space on Hard Drive.

The warinng for Disk space is very annoying and popups up on every GNOME boot. Actually the hard drive with Low disk space is and old mounted partition in NTFS and I only use it to read data.

Here is how to disable HDD Notification Warnings in GNOME:

debian:~# chmod 0000 /usr/lib/gnome-disk-utility/gdu-notification-daemon

phpMyAdmin No activity within 1440 seconds; please log in again Fix

Friday, July 5th, 2013

phpmyadmin no activity within 1440 seconds please log in again screenshot Debian Gnu Linux
I had some complains from Web Developers who constantly was working on a Testing Web Development server. That their opened PhpMyadmin in browser is often closing opened session (auto logging out) with an error:
 

No activity within 1440 seconds; please log in again

This message was driving crazy people, as often they code something in PHP and design a new table or something and refreshing in browser blocked their work flow process with this annoying error …

Thanksfully there is an easy fix to that, just raise the time limit via /etc/phpmyadmin/config.inc.php

First its necessary to enable cookies authentication (by default it is commented):

Line:

//$cfg['Servers'][$i]['auth_type'] = 'cookie';

should be:

$cfg['Servers'][$i]['auth_type'] = 'cookie';

PHPMyAdmin 1140 seconds (24 minutes) timeout behavior behavior is controlled through variable: cfg['LoginCookieValidity']
Also it is necessary to increase timeout from server php.ini  (in Debian and Ubuntu via /etc/php5/apache2/php.ini or in CentOS / RHEL / Fedora Linux by editting /etc/php.ini and changing 1h session expiry setting:

session.gc_maxlifetime = 3600

to

(60*60*8  = 28800 – 8 hrs)

session.gc_maxlifetime = 28800

By default cfg['LoginCookieValidity'] is omitted from config.inc.php so you have to insert it at end of file.

A reasonable timeout value is 8 hours. To change PhPMyadmin Login TimeOut to 8 hours:

$cfg['LoginCookieValidity'] = 60 * 60 * 8; // in seconds (8 hours)

If you want to make Timeout Expire almost never (and you don't care about security) set it to some extra high timeout like 1 year  🙂

$cfg['LoginCookieValidity'] = 3600 * 24 * 365; // 1 year
 

How to make a mirror of website on GNU / Linux with wget / Few tips on wget site mirroring

Wednesday, February 22nd, 2012

how-to-make-mirror-of-website-on-linux-wget

Everyone who used Linux is probably familiar with wget or has used this handy download console tools at least thousand of times. Not so many Desktop GNU / Linux users like Ubuntu and Fedora Linux users had tried using wget to do something more than single files download.
Actually wget is not so popular as it used to be in earlier linux days. I've noticed the tendency for newer Linux users to prefer using curl (I don't know why).

With all said I'm sure there is plenty of Linux users curious on how a website mirror can be made through wget.
This article will briefly suggest few ways to do website mirroring on linux / bsd as wget is both available on those two free operating systems.

1. Most Simple exact mirror copy of website

The most basic use of wget's mirror capabilities is by using wget's -mirror argument:

# wget -m http://website-to-mirror.com/sub-directory/

Creating a mirror like this is not a very good practice, as the links of the mirrored pages will still link to external URLs. In other words link URL will not pointing to your local copy and therefore if you're not connected to the internet and try to browse random links of the webpage you will end up with many links which are not opening because you don't have internet connection.

2. Mirroring with rewritting links to point to localhost and in between download page delay

Making mirror with wget can put an heavy load on the remote server as it fetches the files as quick as the bandwidth allows it. On heavy servers rapid downloads with wget can significantly reduce the download server responce time. Even on a some high-loaded servers it can cause the server to hang completely.
Hence mirroring pages with wget without explicity setting delay in between each page download, could be considered by remote server as a kind of DoS – (denial of service) attack. Even some site administrators have already set firewall rules or web server modules configured like Apache mod_security which filter requests to IPs which are doing too frequent HTTP GET /POST requests to the web server.
To make wget delay with a 10 seconds download between mirrored pages use:

# wget -mk -w 10 -np --random-wait http://website-to-mirror.com/sub-directory/

The -mk stands for -m/-mirror and -k / shortcut argument for –convert-links (make links point locally), –random-wait tells wget to make random waits between o and 10 seconds between each page download request.

3. Mirror / retrieve website sub directory ignoring robots.txt "mirror restrictions"

Some websites has a robots.txt which restricts content download with clients like wget, curl or even prohibits, crawlers to download their website pages completely.

/robots.txt restrictions are not a problem as wget has an option to disable robots.txt checking when downloading.
Getting around the robots.txt restrictions with wget is possible through -e robots=off option.
For instance if you want to make a local mirror copy of the whole sub-directory with all links and do it with a delay of 10 seconds between each consequential page request without reading at all the robots.txt allow/forbid rules:

# wget -mk -w 10 -np -e robots=off --random-wait http://website-to-mirror.com/sub-directory/

4. Mirror website which is prohibiting Download managers like flashget, getright, go!zilla etc.

Sometimes when try to use wget to make a mirror copy of an entire site domain subdirectory or the root site domain, you get an error similar to:

Sorry, but the download manager you are using to view this site is not supported.
We do not support use of such download managers as flashget, go!zilla, or getright

This message is produced by the site dynamic generation language PHP / ASP / JSP etc. used, as the website code is written to check on the browser UserAgent sent.
wget's default sent UserAgent to the remote webserver is:
Wget/1.11.4

As this is not a common desktop browser useragent many webmasters configure their websites to only accept well known established desktop browser useragents sent by client browsers.
Here are few typical user agents which identify a desktop browser:
 

  • Mozilla/5.0 (Windows NT 6.1; rv:6.0) Gecko/20110814 Firefox/6.0
  • Mozilla/5.0 (X11; Linux i686; rv:6.0) Gecko/20100101 Firefox/6.0
  • Mozilla/6.0 (Macintosh; I; Intel Mac OS X 11_7_9; de-LI; rv:1.9b4) Gecko/2012010317 Firefox/10.0a4
  • Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:2.2a1pre) Gecko/20110324 Firefox/4.2a1pre

etc. etc.

If you're trying to mirror a website which has implied some kind of useragent restriction based on some "valid" useragent, wget has the -U option enabling you to fake the useragent.

If you get the Sorry but the download manager you are using to view this site is not supported , fake / change wget's UserAgent with cmd:

# wget -mk -w 10 -np -e robots=off \
--random-wait
--referer="http://www.google.com" \--user-agent="Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6" \--header="Accept:text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5" \--header="Accept-Language: en-us,en;q=0.5" \--header="Accept-Encoding: gzip,deflate" \--header="Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7" \--header="Keep-Alive: 300"

For the sake of some wget anonimity – to make wget permanently hide its user agent and pretend like a Mozilla Firefox running on MS Windows XP use .wgetrc like this in home directory.

5. Make a complete mirror of a website under a domain name

To retrieve complete working copy of a site with wget a good way is like so:

# wget -rkpNl5 -w 10 --random-wait www.website-to-mirror.com

Where the arguments meaning is:
-r – Retrieve recursively
-k – Convert the links in documents to make them suitable for local viewing
-p – Download everything (inline images, sounds and referenced stylesheets etc.)
-N – Turn on time-stamping
-l5 – Specify recursion maximum depth level of 5

6. Make a dynamic pages static site mirror, by converting CGI, ASP, PHP etc. to HTML for offline browsing

It is often websites pages are ending in a .php / .asp / .cgi … extensions. An example of what I mean is for instance the URL http://php.net/manual/en/tutorial.php. You see the url page is tutorial.php once mirrored with wget the local copy will also end up in .php and therefore will not be suitable for local browsing as .php extension is not understood how to interpret by the local browser.
Therefore to copy website with a non-html extension and make it offline browsable in HTML there is the –html-extension option e.g.:

# wget -mk -w 10 -np -e robots=off \
--random-wait \
--convert-links http://www.website-to-mirror.com

A good practice in mirror making is to set a download limit rate. Setting such rate is both good for UP and DOWN side (the local host where downloading and remote server). download-limit is also useful when mirroring websites consisting of many enormous files (documental movies, some music etc.).
To set a download limit to add –limit-rate= option. Passing by to wget –limit-rate=200K would limit download speed to 200KB.

Other useful thing to assure wget has made an accurate mirror is wget logging. To use it pass -o ./my_mirror.log to wget.
 

Frogatto & Friends – One of the TOP 10 Arcade Free Software & Open Source Games for GNU / Linux and FreeBSD

Friday, December 16th, 2011

Frogatto old-school 2d jump and run free software game for GNU / Linux and FreeBSD
1. Frogatto & Friends – Is an Indian Free Software (Open Source) game in the spirit of old-school jump’en runs like Commander Keen, Prehistoric, Jazz Jack Rabbit

The game is really entertaining, the graphics looks approximately nice, the music is awesome, the gamelplay is good even though after some point in the game the moment with “where should I go now, I can’t find exit” comes through and it gets boring.

Generally if you compare with all the existing jump and run arcade games free software games available for Linux and FreeBSD the game will definetely arrange itself in the list of TOP 10 free software Arcade Games
and therefore its my own believe that Frogatto is a game that every GNU / Linux and FreeBSD desktop should have in Application -> Games GNOME menu.

Frogatto is rich of levels, enemies obstacles objects, places to visit (which puts it ahead of many of the linux arcade games which often miss enough game levels, has a too short game plots, or simply miss overall game diversity).

Frogatto linux freebsd game bombing airplaine

The game’s general look & feel is like a professional game and not just some tiny free software arcade, made by its authors for the sake to learn some programming, graphics or music creation.
Frogatto door leading to Grotto

Frogatto Free Software game wood screenshot

Besides that Frogatto & Friends is multi-platform supporting all the major operating systems.
Game supports:
 

  • Windows
  • Mac
  • iPhone
  • Debian GNU / Linux
  • FreeBSD

The game source code is also available on Frogatto.com – The Game’s Official website

The game is available as a deb package in Debian and Ubuntu GNU / Linuxes so to install on those deb based distributions, simply use apt:

debian:~# apt-get install frogatto
...

The above command will install two packages frogatto (containing the game’s main executable binary) and frogatto-data containinng all the game textures, levels, graphics, music etc.

BTW the package saparation on a gamename and gamename-data in Debian (for all those who have not still noticed), can be seen on most of the games with a game data that takes more disk space.

After the game is installed the only way to start the game is to run it manually through pressing ALT+F2 in GNOME or running the progrtam through gnome-terminal with cmd:

debian:~$ frogatto

Here are few more Frogatto gameplay screenshots:

Frogatto free open source game screenshot a game bad guy

Frogatto different level screenshot

I’ve noticed Frogatto is also available as an RPM package for Fedora Linux, as well as has a FreeBSD port in the /usr/ports/games/frogatto and this makes it easy to install on most free software OSes in the wild.

While checking frogatto.com , I found an interesting link to a website offering free graphics (pictures), textures and sounds for free and open source games for all those who hold interest into the development of Free Software & Open Source Games make sure you check OpenGameArt.org

OpenGameArt.org looks like a great initiative and will definitely be highly beneficial to the development of more and better FSOS Games so I wish them God speed with this noble initiative.

Frogatto is very suitable for growing kids since it doesn’t contain no violence and every now and then the main game actor the Frogatto Frog leads few lines English dialogues with some of the characters found in the quest.
For none speaking English countries, the game can help the kids to learn some basic english words and thus can help develop kids intellect and knowledge
And oh yeah one more criticism towards the game is the Enlish structure, it seems people who wrote the plot can work this out in the time to come. Many of the English sentences during dialogues the frog leads with the cranks he met does not sound like a common and sometimes even correct english / phrases.

Besides those little game “defect”, the game is pretty awesome and worthy to kill some time and relax from a long stressy day.

How to add a range of virtual IPs to a CentOS and Fedora Linux server

Monday, July 18th, 2011

Recently I had the task to add a range of few IP addresses to as a virtual interface IPs.

The normal way to do that is of course using the all well known ifconfig eth0:0, ifconfig eth0:1 or using a tiny shell script which does it and set it up to run through /etc/rc.local .

However the Redhat guys could omit all this mambo jambo and do it The Redhat way TM 😉 by using a standard method documented in CentOS and RHEL documentation.
Here is how:

# go to network-script directory[root@centos ~]# cd /etc/sysconfig/network-scripts
# create ifcfg-eth0-range (if virtual ips are to be assigned on eth0 lan interface[root@centos network-scripts]# touch ifcfg-eth0-range

Now inside ifcfg-eth0-range, open up with a text editor or use the echo command to put inside:

IPADDR_START=192.168.1.120
IPADDR_END=192.168.1.250
NETMASK=255.255.255.25
CLONENUM_START=0

Now save the /etc/sysconfig/network-scripts/ifcfg-eth0-range file and finally restart centos networking via the network script:

[root@centos network-scripts]# service network restart

That’s all now after the network gets reinitialized all the IPs starting with 192.168.1.120 and ending in 192.168.1.250< will get assigned as virtual IPs for eth0 interface
Cheers 😉