DNS on Windows Server 2003, 3rd Edition

Using DNSLint

DNSLint, which we introduced back in Chapter 8, can also come in handy when you’re troubleshooting. In Chapter 8, we mostly used it to verify the registration of records by Domain Controllers. But DNSLint can also come in handy in detecting delegation problems, as we showed in Chapter 9.

To use DNSLint to check delegation, use the /d command-line option. Specify the domain name of the zone whose delegation you’d like to check as the argument. For example:

C:\> dnslint /d movie.edu
         

This produces a report on movie.edu’s delegation, displayed in a browser window. If you’re checking a zone that’s not registered on the InterNIC’s whois servers (i.e., a subdomain of com or net), you’ll also need to specify the /s option and, as an argument, the IP address of a name server authoritative for the zone.

By default, DNSLint checks DNS over UDP. You can instruct it to test DNS over TCP, too, using the /test_tcp option.

Finally, you can use the /c option to tell DNSLint to check connectivity to the mail ports (SMTP, POP, and IMAP, by default) on the mail servers it finds for the zone. If you don’t want it to check all three, you can enumerate the protocols to check after the option; for example:

C:\> dnslint /d movie.edu /c smtp,imap
         

Here’s some sample DNSLint output (in text format, generated using /t):

DNSLint Report System Date: Sat Jul 05 18:58:05 2003 Command run: dnslint /d fx.movie.edu /t /s 192.253.254.2 /c smtp Domain name tested: fx.movie.edu DNS servers were identified ...