Nslookup

Unlike the ping/tracert tools, nslookup lets you troubleshoot problems with dns and the nameserver entries.

Simple nslookup:

At the command prompt, enter 'nslookup ngeorgia.com' and the reply should look like this:

C:\>nslookup ngeorgia.com
Server: www
Address: xxx.xxx.xxx.xxx

Non-authoritative answer:
Name: ngeorgia.com
Address: 66.40.224.56

This tells you that domain ngeorgia.com is located at ip address 66.40.224.56. It does not validate the route to the server

Complex nslookup

There are many things that can be done with nslookup, some are fairly esoteric. To begin an interactive session, key nslookup at the command prompt.

C:\>nslookup
Default Server: www
Address: 128.2.0.25

The system responds with a "greater than" sign, without a root directory or path.

>

You can key in a domain name and find the nameserver's A record. In addition to the A record, for a domain to correctly route email it must have both an A record and an MX (or mail exchange) record. It is becoming common to designate the address mail.yourdomain.com as the mail server, but many people simply use the domain's A record as the mail server's A record.

To view the MX records for a web site, enter:

>set type=MX
>yahoo.com

> set type=MX
> yahoo.com
Server: www
Address: 128.2.0.25

Non-authoritative answer:
yahoo.com MX preference = 5, mail exchanger = mx4.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = mx1.mail.yahoo.com
yahoo.com MX preference = 1, mail exchanger = mx2.mail.yahoo.com

mx4.mail.yahoo.com internet address = 64.156.215.7
mx4.mail.yahoo.com internet address = 66.218.86.254
mx4.mail.yahoo.com internet address = 66.218.86.253
mx4.mail.yahoo.com internet address = 216.136.129.5
mx4.mail.yahoo.com internet address = 66.218.86.156
mx1.mail.yahoo.com internet address = 64.156.215.6
mx1.mail.yahoo.com internet address = 64.157.4.78
mx1.mail.yahoo.com internet address = 64.157.4.79
mx1.mail.yahoo.com internet address = 64.156.215.5
mx2.mail.yahoo.com internet address = 64.156.215.5
mx2.mail.yahoo.com internet address = 64.156.215.6
mx2.mail.yahoo.com internet address = 64.157.4.78