Looking Up Domains and Hosts with Nslookup
CS 3000 -- Lab Assignment #6
DIRECTIONS: Before you start, scan the man page for nslookup.
When you do the lab, type nslookup commands equivalent to the ones
you see typed below, and examine the output. Ask questions.
/* Start interactive nslookup. */
john@alcyone: nslookup
Default Server: altair.csustan.edu
Address: 130.17.1.50
/* Select the primary nameserver at Cal Tech.
We got the domain name while doing a previous lab (whois).
We used the command:
whois -h whois.networksolutions.com caltech.edu */
> server MERCUTIO.NI.CALTECH.EDU
Default Server: MERCUTIO.NI.CALTECH.EDU
Address: 131.215.254.99
/* Enter a host names we got from a web search. See if the nameserver
gives a translation to an IP number. */
> www.cs.caltech.edu
Server: MERCUTIO.NI.CALTECH.EDU
Address: 131.215.254.99
Name: squid.cs.caltech.edu
Address: 131.215.44.93
Aliases: www.cs.caltech.edu
>
/* Tell nslookup you want to get info about mail hubs for hosts. */
> set querytype=MX
/* Get info about this host. */
> squid.cs.caltech.edu
Server: MERCUTIO.NI.CALTECH.EDU
Address: 131.215.254.99
cs.caltech.edu
origin = namae.cs.caltech.edu
mail addr = hostmaster.cs.caltech.edu
serial = 10091657
refresh = 43200 (12H)
retry = 3600 (1H)
expire = 3628800 (6W)
minimum ttl = 3600 (1H)
>
/* Ask Mercutio to give us a complete list of all the hosts
in its database for the domain cs.caltech.edu. */
> ls -d cs.caltech.edu
[MERCUTIO.NI.CALTECH.EDU]
$ORIGIN cs.caltech.edu.
@ 3H IN SOA namae hostmaster (
10091657 ; serial
12H ; refresh
1H ; retry
6W ; expiry
1H ) ; minimum
3H IN NS namae
3H IN NS ravel
3H IN NS tepid.ni.caltech.edu.
3H IN NS tybalt.caltech.edu.
3H IN NS mercutio.ni.caltech.edu.
3H IN A 131.215.45.109
3H IN MX 0 mailhost
3H IN MX 10 obento
abacus 3H IN CNAME abekas.gg.caltech.edu.
abekas 3H IN CNAME abekas.gg.caltech.edu.
above 3H IN CNAME above.ugcs.caltech.edu.
abstract 3H IN A 131.215.45.96
acap 3H IN A 131.215.44.17
actel 3H IN CNAME actel.pcmp.caltech.edu.
against 3H IN CNAME against.ugcs.caltech.edu.
alaincable 3H IN A 131.215.185.187
almaz 3H IN A 131.215.44.177
alpaugh 3H IN A 131.215.44.171
amber 3H IN A 131.215.45.54
amethyst 3H IN A 131.215.44.64
amiga 3H IN A 131.215.44.132
3H IN MX 0 mailhost
amongst 3H IN CNAME amongst.ugcs.caltech.edu.
anaheim 3H IN A 131.215.44.89
ansible 3H IN A 131.215.44.137
antigen 3H IN A 131.215.44.11
anvil 3H IN CNAME anvil.pcmp.caltech.edu.
apoggo 3H IN CNAME apoggo.gg.caltech.edu.
apollo 3H IN CNAME apollo.gg.caltech.edu.
appleII 3H IN A 131.215.44.18
aristotle 3H IN A 131.215.44.7
3H IN MX 0 mailhost
around 3H IN CNAME around.ugcs.caltech.edu.
arpeggio 3H IN CNAME arpeggio.gg.caltech.edu.
ascend 3H IN A 131.215.44.71
astride 3H IN CNAME astride.ugcs.caltech.edu.
async 3H IN CNAME async.async.caltech.edu.
atari 3H IN A 131.215.44.68
atop 3H IN CNAME atop.ugcs.caltech.edu.
avenal 3H IN A 131.215.44.115
babylon 3H IN A 131.215.44.6
3H IN MX 0 mail.tffenterprises.com.
3H IN MX 10 mail2.tffenterprises.com.
backup 3H IN A 131.215.44.181
baroque 3H IN A 131.215.45.106
bauhaus 3H IN A 131.215.45.85
behind 3H IN CNAME behind.ugcs.caltech.edu.
below 3H IN CNAME below.ugcs.caltech.edu.
ben 3H IN A 131.215.45.56
/* There were a lot more hosts. I deleted the rest of the information.
*/
/* Get back into the mode in which nslookup translates from
domain names to IP numbers. */
> set querytype=A
/* Set the current hostname to squid */
> squid.cs.caltech.edu
Server: MERCUTIO.NI.CALTECH.EDU
Address: 131.215.254.99
Name: squid.cs.caltech.edu
Address: 131.215.44.93
>
/* Ask who is logged on to squid */
> finger
finger: connect: Connection refused
/* The request was refused for this host. I did a web search to try to
find a more "student oriented" machine. I came up with a host that does
respond to finger. */
> www.gps.caltech.edu
Server: MERCUTIO.NI.CALTECH.EDU
Address: 131.215.254.99
Name: wwwftp.gps.caltech.edu
Address: 131.215.65.167
Aliases: www.gps.caltech.edu
> finger
[wwwftp.gps.caltech.edu]
Login Name TTY Idle When Where
rt Super-User pts/2 1:36 Mon 11:38 mochtbu
/* See what specific information we can get about "rt" */
> finger rt
[wwwftp.gps.caltech.edu]
Login name: rt In real life: Super-User
Directory: / Shell: /opt/util/bin/tcsh
On since Oct 7 11:38:36 on pts/2 from mochtbu
1 hour 43 minutes Idle Time
No unread mail
No Plan.
/* Try a "generic" name to see how much information we can get: */
> finger john
[wwwftp.gps.caltech.edu]
Login name: grotz In real life: John P. Grotzinger
Directory: /home/grotz Shell: /opt/util/bin/tcsh
Never logged in.
No unread mail
No Plan.
Login name: kinmtrcs In real life: John Walsh
Directory: /home/kinmtrcs Shell: /opt/util/bin/tcsh
Never logged in.
No unread mail
No Plan.
Login name: jholt In real life: John Holt
Directory: /home/jholt Shell: /opt/util/bin/tcsh
Never logged in.
No unread mail
No Plan.
Login name: johna In real life: John Armstrong
Directory: /home/johna Shell: /opt/util/bin/tcsh
Never logged in.
No unread mail
Project: No project yet...
No Plan.
Login name: jtoth In real life: John Toth
Directory: /home/jtoth Shell: /opt/util/bin/tcsh
Never logged in.
New mail received Fri Oct 11 18:52:44 2002;
unread since Fri Aug 10 10:34:52 2001
No Plan.
Login name: markwis In real life: John Marquis
Directory: /home/markwis Shell: /opt/util/bin/tcsh
Last login Tue Oct 2, 2001 on pts/4 from earth
New mail received Tue Oct 15 09:05:20 2002;
unread since Thu Oct 10 13:32:43 2002
Plan:
To actually have a plan.
To change it every so often.
To keep hammering away at my work.
/* There were a lot more records of users. I deleted the rest of the
information. */
/* Note: Sometimes you can get more "finger information" by doing what we did
above than the information you would get by just executing the command
finger john@www.gps.caltech.edu
at a unix prompt. (Try it.) */
/* Change the nameserver. This time it is one of our department Mac's
that runs named. */
> server splendor.csustan.edu
Default Server: www.cs.csustan.edu
Address: 130.17.1.35
Aliases: splendor.csustan.edu
>
/* Set the current hostname to POLLUX. */
> pollux
Server: www.cs.csustan.edu
Address: 130.17.1.35
Aliases: splendor.csustan.edu
Name: pollux.csustan.edu
Address: 130.17.1.55
>
/* Ask who is logged on to POLLUX. */
> finger
[pollux.csustan.edu]
Login Name TTY Idle When Where
zoller Phillip W. Zoller pts/4 6d Wed 14:26 pzoller-sun.cisco.co
majordom MajorDomo Account pts/5 21: Thu 14:56 eos.csustan.edu
rayz R. L. Zarling *pts/6 Tue 13:08 hexe.csustan.edu
> exit