To find the processor type and details
Get the Processor details:

cat /proc/cpuinfo

Find whether the processor is 32 or 64 bit:

 getconf LONG_BIT

Find the architecture:

uname -i

 Ping Requests use ICMP protocols. This is enabled/disabled using sysctl values.
To Disable Ping:
 
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all
 
To Enable Ping:
 
echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

Install openvpn using the rpm
Installing OpenVPN from a binary RPM package has these dependencies:

openssl
lzo
pamInstall rpms as root:# rpm -ivh openvpn-2.0.5-1.el4.rf.i386.rpm

 
installing rpm 
 

    rpm -ivh lzo-1.08-4.2.el4.rf.i386.rpm

 The main configuration directory for open vpn is /etc/openvpn
Setting up your Certificate Authority (CA) and generating certificates and keys for …

This comes into picture when one Admin doesn’t have physical access to a system in which Linux needs to be installed. Here we need help from one person who is having physical access to that remote machine to get it booted from bootable media and to type the command shown …

Please follow the below steps to disable a specific command(s) for a certain user.
# su – riyesh
$ which rm (Here rm command as an example)
$ mkdir ~/bin
$ ln -s /bin/* ~/bin/ (/bin is the PATH for rm)
$ rm -rf ~/bin/rm
Take the output of $PATH for this user
$ echo $PATH > …

 
Create vnc passwd
x11vnc -storepasswd
Use authentication while connecting
x11vnc -rfbauth ~/.vnc/passwd
Keep the VNC Session after each login and logout
x11vnc -forever
Don’t use shm of X if you have problems in display
x11vnc -noshm
So the final command is
x11vnc -noshm -forever -rfbauth ~/.vnc/passwd
Finished