Linux

You know how telnet works in linux..

In general xinetd will be listening for general daemons like ssh & telnet. When telnet request comes, xinetd handovers the control to telnetd and it inturn starts login which

xinetd--->telnetd--->login--->shell
xinetd--->sshd--->shell

PAM: Pluggable Authentication Modules
PAM is a library.
Through the PAM we can customize our the authentication methods.
For example: telnet spawns login. login will be having dependency on libpam.so. libpam.so reads the configuration file where we can define our customized authentication method(as a library) or we can use default linux authentication method.

similar to login for telnet, sshd will be having dependency on libpam.so.

To know the installed packages in linux:
Fedora:
#yum list installed 
#rpm -qa
Ubuntun:
#dpkg --get-selections

Linux repositories are at:
#ls /etc/yum.repos.d/*  OR
#cat /etc/yum.conf

Installing firefox in fedora:
http://www.if-not-true-then-false.com/2011/install-firefox-5-on-fedora/ 

To add new search plugin to firefox:
cp cisco.xml /usr/lib64/firefox/searchplugins/




Difference between zombie & orphan process