1. NETWORKING IN LINUX

2. WHAT IS LINUX..? Freely implemention of UNIX-like Kernel. Free & Open source Software. Developed by Linus Torvalds in 1991.

3. Evolution of Linux Kernel  First Linux Version 0.01 released on May 14 th 1991.  Second Linux Version 1.0 released on March 14 th 1994.  Third Linux Version 2.0 released on June 1996.

4.  Fourth Linux Version 2.2 released on Jan 1999.  Fifth Linux Version 2.4 released in January 2001.  Latest Linux Version 2.6 released in December 2003.

5. SELinux Security Enhanced Linux Clean separation of policy from enforcement Independent of specific policies and policy languages Caching of access decisions for efficiency # Support for policy changes

6. Basic Networking Tools PING: anshu@anshu-desktop:~$ ping www.google.com PING www.l.google.com (209.85.153.104) 56(84) bytes of data. 64 bytes from im-in-f104.google.com (209.85.153.104): icmp_seq=1 ttl=247 time=98.4 ms 64 bytes from im-in-f104.google.com (209.85.153.104): icmp_seq=2 ttl=247 time=84.7 ms --- www.l.google.com ping statistics --- 3 packets transmitted, 2 received, 33% packet loss, time 1998ms rtt min/avg/max/mdev = 84.769/91.601/98.434/6.839 ms

7. NETSTAT : anshu@anshu-desktop:~$ netstat -r Kernel IP routing table Destination Gateway Genmask Flags MSS Window irtt Iface 122.50.192.0 * 255.255.252.0 U 0 0 0 eth0 link-local * 255.255.0.0 U 0 0 0 eth0

8. IFCONFIG : ifconfig is used to configure the kernel-resident network interfaces. It is used at boot time to set up interfaces as necessary. After that, it is usually only needed when debugging or when system tuning is needed.

9.  NSLOOKUP: anshu@anshu-desktop:~$ nslookup www.google.com www.google.com Server: 202.62.224.2 Address: 202.62.224.2#53 Non-authoritative answer: www.google.com canonical name = www.l.google.com. Name: www.l.google.com Address: 209.85.153.104

10.  TRACEROUTE: anshu@anshu-desktop:~$ traceroute www.iacr.ac.in traceroute to www.iacr.ac.in (206.105.196.68), 30 hops max, 40 byte packets

11.  NMAP: anshu@anshu-desktop:~$ nmap -A www.iacr.ac.in Starting Nmap 4.53 ( http://insecure.org ) at 2008-07-24 00:01 IST SCRIPT ENGINE: rpcinfo.nse is not a file. SCRIPT ENGINE: Aborting script scan. Interesting ports on www.silicon.ac.in (206.105.196.68):www.silicon.ac.in

12. Internet Services Telnet: anshu@anshu-desktop:~$ telnet www.iacr.ac.inTrying 206.105.196.68... Connected to www.iacr.ac.in. Escape character is '^]'. CentOS release 4.4 (Final) ‏ Kernel 2.6.9-42.0.10.ELsmp on an i686 login:

13. Secure Shell (SSH): anshu@anshu-desktop:~$ ssh www.iacr.ac.in The authenticity of host 'www.iacr.ac.in (206.105.196.68)' can't be established. RSA key fingerprint is 5a:9b:1d:e8:d7:ad:a8:cf:58:66:49:77:1f:24:13:88. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'www.iacr.ac.in,206.105.196.68' (RSA) to the list of known hosts. anshu@www.iacr.ac.in's password:

14. File Transfer Protocol (FTP): anshu@anshu-desktop:~$ ftp ftp.kernel.org Connected to pub.us.kernel.org. 220 Welcome to ftp.kernel.org. Name (ftp.kernel.org:saurabh): anonymous 331 Please specify the password. Password:

15. Secure Copy (SCP): The syntax for scp is: scp user@host:file1 user@host file2user@host

16. Secure File Transfer Program (SFTP): The syntax for sftp is: sftp user@host: file fileuser@host

17. FINGER: anshu@anshu-desktop:~$ finger anshu Login: anshu Name: anshu Kumar Directory: /home/anshu Shell: /bin/bash On since Wed Jul 23 09:06 (IST) on tty7 from :0 On since Wed Jul 23 12:12 (IST) on pts/0 from :0.0 No mail. No Plan.

18. The SAMBA Server: Their own logins on all the home windows boxes while having their files on the Linux box appear to be located on a new Windows drive. Shared access to printers on the Linux box Shared files accessible only to members of their Linux user group.

19. The Web Server Apache: Apache, is a web server notable for playing a key role in the initial growth of the World Wide Web. Apache was the first viable alternative to the Netscape Communications Corporation web server (currently known as Sun Java System Web Server), and has since evolved to rival other Unix- based web servers in terms of functionality and performance.

20. Network File System Protocol : Linux data storage disks contain files stored in file systems with a standardized directory structure. New disks are added by attaching, or mounting, the directories of their file systems to a directory of an already existing file system. This in effect makes the new hard disk transparently appear to be a subdirectory of the file system to which it is attached.

21. The SENDMAIL: Post Office Protocol version-3 SMTP IMAP

22. References http://www.linux.org http://en.wikipedia.org/selinux IEEE Papers like: Analysis and Study of Security Mechanism Inside Linux Kernel