NETWORK BASICS

1. Login to one of the Sun Ultra's. See who else is logged on by using these commands:
   
   
   • finger
   • w
   • who
   
   commands. Notice the differences among the displays. Do
   
   finger @pollux
   
   to see who is logged in on pollux. Do
   
   finger @altair
   
   to see if anyone is logged in on altair.
   
   Do some commands of the form
   
   finger user
   
   where, for user, you substitute the first name, last name, or user name of someone who has an account on the computer you are logged into. (You may choose one of your classmates.)
   
   The names of the Sun Ultra's in the lab are:
   
   altair, arcturus, barnard, capella, castor, centauri, ceti, deneb, omicron, polaris, pollux, regulus, rigel, saiph, sirius, sol, soleil, spica, vega, and zaurak.
   
   Do some commands of the form
   
   finger @hostname
   
   where you make hostname one of the names of the Sun Ultra's. Are the results what you expect? Do they agree with the signs on the computers and the identities of the people you see sitting in front of the computers?
   
   
2. Read the manual page for the netstat command by executing:
   
   man netstat
   
   and look at the -n and -r options. Do the command:
   
   netstat -nr
   
   Try to figure out what the output means. Try the command:
   
   netstat -r
   
   Does that make the output more understandable?
   
   
3. Read the man page for the arp command.
   
   Execute this command
   
   arp -a | less
   
   What does the output mean?
   
   
4. Read the man page for the ifconfig command.
   
   Enter this command:
   
   ifconfig -a
   
   Try to figure out what the output means.
   
   Ask your instructor to run the command as super-user sometime - so you can see the address of the ethernet interface.
   
   
5. Do
   
   man route
   
   Ask your instructor to show you the scripts used on alcyone to connect it to a subnet via ppp.