Linux Internet Servers:-

•     Web – Apache HTTP Server, Apache Tomcat
•     Databases – MySQL, PostgreSQL, Oracle
•     Programming and scripting – PHP, Java, Perl,
•     JavaScript, CSS, XHTML, Bash
•     FTP – ProFTPD, Pure-FTPd, vsftpd
•     SMTP (outgoing email) – exim, postfix, qmail, sendmail
•     POP3 and IMAP (incoming email) – qpopper, UW IMAP, Courier-IMAP
•     DNS (Domain Name System) – BIND, djbdns
•     Web control panels – cPanel and WebHost Manager
•    Plesk, DirectAdmin, Webmin

Linux Virtualization:-

•     VMware ESX, ESXi, VMware Server
•     Xen – Amazon EC2 Cloud, Citrix XenServer
•     User Mode Linux (UML)
•     Manage Large Networks (MLN)
•     Linux Remote Access:-
•     SSH (Secure SHell) – OpenSSH
•     VNC (Virtual Network Computing)
•     X Window System (X.Org, X11)
•     OpenVPN

Linux Security:-

•     Network monitoring – SNMP, Nagios, Big Brother/Hobbit, MRTG, Cacti
•     SSL/TLS encryption – OpenSSL, stunnel
•     Intrusion Detection Systems (IDSs) – Snort
•     Tripwire (file integrity checker)

Linux Internal Network Servers:-

•     File server – Samba (SMB, CIFS), NFS, iSCSI
•     LDAP (directory services) – OpenLDAP
•     DHCP – ISC DHCP
•     Routing – Quagga, OSPF, RIP, VRRP, CARP

Linux Distributions:-

•     Red Hat Enterprise Linux (RHEL)
•     CentOS
•     SUSE Linux Enterprise Server (SLES)
•     Debian GNU/Linux
•     Ubuntu Server and Desktop Editions
•     openSUSE
•     Fedora