Homework 8

Purpose: Networking details

1. Find the hostname of the local computer (Hint: use the "hostname" command).

2. Find the IP address of the local computer. Try the "host" command with the host name as an argument, then with the IP address with an argument.

3. Find more details about the network interfaces on the computer using the "ifconfig" command. (Hint: the ifconfig binary may not be in the path, search for it.) Try to identify the MAC address and figure out what is the meaning of the rest of the info.

4. Explore the routing tables of the computer using the "route" command.

5. Test the link between two computers using "ping" and explore the routers involved in the communication using "traceroute". Read the manual pages and understand the meaning of the output.

6. Use ssh to login to a remote computer from several xterms. Monitor the forking of the sshd daemon processes with the number of incoming connections. Use "pstree" to see how are these processes related.

7. What would be the broadcast and the network addresses for a computer with the IP address 128.2.32.144, netmask 255.255.255.196.

8. Eplore the active network connections on the computer using the "netstat" command.

9. Find the files used by different processes using the "lsof" command. Read the manual page. Can you figure out what options to use to find the ports open by network services?