To change the SSH port number login as root, and edit /etc/ssh/sshd_config

Find the line that says Port 22 and change 22 to any number between 1024->65535 (above 30000 is best) and save the file.

Once done, run:

/etc/init.d/sshd restart

Now start a new SSH session (don’t close your existing one), to make sure that you can get in.

Log into SSH

mkdir $HOME/.ssh
chmod -R og= $HOME/.ssh
cd .ssh
nano authorized_keys2

Add your key you created with PuttyGen , make absolutly sure you r key is in one line ONLY , otherwise it wont work!

Adjust your  sshd_config

nano /etc/ssh/sshd_config

to

RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile      .ssh/authorized_keys2

check what kernel you are running at the moment

uname -a

and to upgrade your kernel

yum update \kernel*

check if your kernel is added to grub

cat /boot/grub/grub.conf

and then reboot

shutdown -rf now

Need to know the exact size of your subdirectories in Linux?

Just go to the directory , like cd / and try this

du -cksh *

For whatever reason CentOS decided to drop netconfig and renamed it to

system-config-network

If rpm / yum command hangs during operations or you see error messages - it means your rpm database corrupted. /var/lib/rpm/ stores rpm database just delete the same and rebuild rpm database:

Command to rebuild rpm database

rm -f /var/lib/rpm/__db*
rpm --rebuilddb -v -v

Read rpm / yum man pages for more information

OK, so you are ready to move your server to a different datacenter with a different IP C class.

Here are a few things you need to change

For whatever reason , some people still want to run the old version of MySQL4.1 in there new cPanel servers, which seems a little issue , as the default database version in new cPanel server installs is MySQL5.

Here are the simple steps to downgrade the database (this should only be done on a new server without any account on it yet)

Had an issue with one on our CentOS cPanel servers running 64 bit and cPanels easyapache upgrade. The folks at cPanel helped out with their usual professional response

 Open SSH and type the following and press Enter:

/sbin/ifconfig | grep -i hwaddr

The sequence of hexadecimal digits that appears to the right of eth0 HWAddr (e.g. 08:00:27:ED:DA:8b) is your network card's MAC Address

Sometime accounts are to big to transfer via the WHM transfer feature.

Below you can find some steps to do so manually 

If you have issues with cPanel running CentOS5 with BIND then the easiest way is to downgrade BIND to 9.2.4

The reason you're having trouble is because CentOS 5 uses bind-9.3 and CentOS 4 uses bind-9.2 - The changes between these versions is significant enough that cPanel won't work with it properly.

For instance by default there is no /etc/named.conf file created when bind-9.3 is installed and the default named.conf file for bind-9.3 is significantly different than in older versions.

Until the code is updated to work with bind-9.3, I have found the workaround to be to remove bind-9.3 packages and install bind-9.2 packages as follows:
 

SystemRescueCD is a powerful, expansive live cd which is useful for recovering broken systems. This tutorial will guide you through how to get it up and running and how to perform some basic recovery procedures.

Server monitoring is one of the most important aspects of managing a network. Cacti is a free PHP/MySQL script which can monitor everything from process counts to bandwidth, and is fairly easy to setup and use. If you have multiple clients you can even delegate specific access levels so that they can only view the graphs relevant to them.

This tutorial will guide you through setting up and configuring Cacti on a Linux server. 

While the big control panel suites you can install, like cPanel or Plesk, are excellent for large scale deployments or easy system administration, sometimes you just want an interface to quickly carry out complex tasks, which doesn't require a package as large as cPanel/Plesk.

Webmin, a free and powerful control panel, it easy to install and allows you to carry out administrative tasks in an easy to use browser based frontend. This tutorial will guide you through installing Webmin.