Linux

Tips for Linux Users

Need better SPAM guard with Qmail

i have used QMail as MTA in Linux and simple web based PHP script for mail box. the smtp is Qmail-smtpd and pop is qmail-pop3d. i have used spam guard as SpamAssassign 3.0.3 and qmail scanner 2.0.1 with clamd antivirus 0.88.5. all these are latest product as i know but what a problem i am facing with this setup is still i am not able to control all SPAM.

So any guys, do you have any idea about how to control SAPM perfectly with Qmail? i will be very very happy with better solution.

Babu Ram Dawadi[baburd], CIT,IOE,TU

Remotely Manage Machines Using VNC

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.

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Ironing out Ubuntu Dapper to Edgy upgrade...

I took the jump from Dapper (6.06) to Edgy (6.10) with quite a flawless upgrade initiated by:

$ gksu "update-manager -c"

Had to comment out the PLF repositories before I could do the upgrade.

## PLF REPOSITORY
# deb http://packages.freecontrib.org/ubuntu/plf dapper free non-free
# deb-src http://packages.freecontrib.org/ubuntu/plf dapper free non-free

The first thing I did after the upgrade was to enable the universe and multiverse repositories via Synaptics and run an upgrade and autoclean via aptitude to clean out any unused and downloaded packages:

$ sudo aptitude upgrade
$ sudo aptitude autoclean

Also noticed that the default shell had been changed to dash instead of the familiar bash on linux distros, so I removed the symbolic link for "/bin/sh" from dash to bash:

$ sudo rm -rf /bin/sh
$ sudo ln -s /bin/bash /bin/sh

The default video driver didn't quite work too well with my nvidia card and so installed nvidia-glx and enabled it.

$ sudo aptitude install nvidia-glx
$ sudo  nvidia-glx-config enable
$ sudo nvidia-xconfig

With the nvidia glx driver and the new kernel installed, I edited "/etc/grub/grub.conf" to point to the new kernel:

title Ubuntu Edgy 386
        root (hd0,2)
        kernel /vmlinuz-2.6.17-10-386 ro root=/dev/mapper/vg00-lv00
        initrd /initrd.img-2.6.17-10-386

Gave the system a reboot and everything seemed to be back to normal... but not until I opened up firefox and noticed the font rendering was blurred and ugly, unlike the crisp fonts on other application. Checked on some of the bug reports at launchpad.net and indeed found a fix there. The fix mentioned was to create a ".font.conf" file with the below contents in the home directory:

<?xml version="1.0"?>r /><!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<match target="font" >
  <edit mode="assign" name="rgba" >
   <const>rgb</const>
  </edit>
</match>
<match target="font" >
  <edit mode="assign" name="hinting" >
   <bool>true</bool><br />  </edit>
</match>
<match target="font" >
  <edit mode="assign" name="hintstyle" >
   <const>hintfull</const>
  </edit>
</match>
<match target="font" >
  <edit mode="assign" name="antialias" >
   <bool>true</bool><br />  </edit>
</match>
</fontconfig>

Tomboy -- a wiki for the desktop had been made available by default with Edgy but did not show up anywhere in the Applications list so added it to the top panel from the list of Accessories available.

Last but not the least my boot time is now about 12 seconds on a 1.75Ghz cpu laptop with 1Gig of memory... all due to the new init system, upstart which is now the default.

Reset forgotten root password on linux boxes...

I had an old computer with linux installed and had forgotten the root password for it. Unfortunately, I did not have my favourite handy-dany knoppix cd around but did remember that I could get a shell access by appending "init=/bin/bash" to the lilo/grub boot loader, which should be enough to get in and reset the root password.

DISCLAIMER -- I do not take any responsibility for your actions if you go and try this on your friends machine!!

  1. Press Ctrl-Alt-Del to shut down the system in an orderly fashion.
  2. Reboot the system and when lilo/grub boot loader get to the point where you select the various installed kernels on the system, type the letter "a" for "append".
  3. You will get a prompt like this to add boot options to the boot string found in your lilo/grub conf file:
    grub append> ro root=LABEL=/
  4. Append "init=/bin/bash" to it to look like this.
    grub append> ro root=LABEL=/ init=/bin/bash

    This tells the kernel to drop to a root prompt bash shell instead of starting the "/sbin/init" process.

  5. The root filesystem is currently mounted read only which needs to be changed to read/write prior to resetting the password.
    # mount -o remount,rw /
  6. Now that the file-system is remounted read-write, go ahead and type `passwd` to change the root password.
    # passwd
  7. Since "init" isn't running to safely take down the system, remount the system to read only prior to shutting down the system.
    # mount -o remount,ro /
  8. You can now safely press on the power button to shutdown the sytem.

Kubuntu 6.06 LTS Installation Walkthrough with Screenshots

Kubuntu is a user friendly operating system based on KDE, the K Desktop Environment. With a predictable 6 month release cycle and part of the Ubuntu project, Kubuntu is the GNU/Linux distribution for everyone.

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Swap fails to mount at boot -- resolved!

At some point of my regular yum updates, I noticed there was no swapspace being mounted at boot time. I was however able to manually mount it after booting via, `swapon -a`.

The failure was caused due to SELinux policy and "/etc/fstab" file context settings. I was getting the below message in my logs:

Sep 17 12:12:36 localhost kernel: audit(1158509512.509:51): avc:  denied  
{ read } for  pid=1429 comm="swapon" name="fstab" dev=dm-0 ino=899639 
scontext=system_u:system_r:fsadm_t:s0 tcontext=system_u:object_r:file_t:s0 tclass=file

I found my solution in the SELinux FAQ

Debian Network Utilities and tools With Examples and man pages

This is the list of debian network utilities and tools for administrators and users to check the network related traffic, monitor network.This includes installation of each package with man pages.This full list devided in to two parts which is part1 network tools and part2 network tools

Debian etch beta 3 graphical mode installation with screenshots

Debian etch beta3 installation using graphical interface this is really nice installation walkthrough with each step
screenshots.This is new feature in debian upcoming release version called etch.This article contains nearly 50 images of this installation process.

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IEs4Linux -- Internet Explorer for Linux

Two reasons why you should get IEs4Linux:

  1. You are a web-designer using Linux and want to test your sites using Internet Explorer as your visitors are predominantly IE users.
  2. You need the latest and greatest flash player with your browser to view sites like ESPN, MetaCafe etc... The latest version of Flash is 9 which is only available to Windows and Macs whereas on the Linux side we have been left behind with 7.

Below is how I got it up and running on Fedora Core 5:

  • Install cabextract and wine if you don't have it already:
    # yum --enablerepo=extras install cabextract wine
    
  • Download and install IEs4Linux:
    $ wget http://www.tatanka.com.br/ies4linux/downloads/ies4linux-2.0.1.tar.gz
    $ tar -xvzf ies4linux-2.0.1.tar.gz
    $ cd ies4linux-2.0.1
    $ ./ies4linux
    
  • Internet Explorer can now be run via the shortcut icon created on the desktop.

Install common Windows fonts on Linux

I have built Microsofts' common true type core fonts for the web and can be downloaded from here.

Below are the steps I took to build the rpm package on FC5:

  1. Install cabextract.
    # yum --enablerepo=extras install cabextract
    
  2. Setup your rpm build environment if you have not done so already.
  3. Login as rpmbuild.
    # su - rpmbuild
    
  4. Dowload the spec file.
    $ cd rpm/SPECS
    $ wget http://corefonts.sourceforge.net/msttcorefonts-2.0-1.spec
    
  5. Build the rpm.
    $ rpmbuild --bb msttcorefonts-2.0-1.spec
    
  6. Install the corefonts and restart xfs as root.
    # rpm -ihv /path/to/msttcorefonts-2.0-1.noarch.rpm
    # service xfs restart
    

If you are looking for more info visit, corefonts.sourceforge.net .

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