DNS on Windows 2000, Second Edition

Good Parenting

Now that the delegation to the fx.movie.edu name servers is in place, we—responsible parents that we are—should check that delegation using host. What? We haven’t given you host yet? A version of host that works on Windows 2000 is available via anonymous ftp from ftp://ftp.nikhef.nl/pub/network/host_970908.exe.Z. To uncompress host, you’ll need WinZip or a similar Windows utility. WinZip is available from http://www.winzip.com.

Once you uncompress host_970908.exe, install it as host.exesomewhere on your computer. (We install it in the same directory as nslookup.exe.) Next, set up a resolv.conffile in your %WINDIR%directory. (If you’re not sure where %WINDIR%is, type set from a DOS prompt.)

hostmakes it easy to check delegation. With host , you can look up the NS records for your zone on your parent zone’s name servers. If those look good, you can use hostto query each name server listed for the zone’s SOA record. The query is nonrecursive, so the name server queried doesn’t query other name servers to find the SOA record. If the name server replies, host checks the reply to see whether the aa (authoritative answer) bit in the reply packet is set. If it is, the name server checks to make sure that the packet contains an answer. If both these criteria are met, the name server is flagged as authoritative for the zone. Otherwise, the name server is not authoritative, and host reports an error.

Why all the fuss over bad delegation? Incorrect delegation can slow ...