CS server hostnames...

[Peter Motyka]

So, it looks like OIT has scrapped the client-xxx-xxx... reverse dns hostname scheme, but what is up with the new one?

# nslookup solar.cs.siue.edu
Server:  boris.vegan.cx
Address:  10.16.0.25

Name:    solar.cs.siue.edu
Address:  146.163.150.6

# nslookup 146.163.150.6
Server:  boris.vegan.cx
Address:  10.16.0.25

Name:    solar.cs.siue.edu.150.163.146.in-addr.arpa
Address:  146.163.150.6

Why do ips have to resolve to such long ugly hostnames?

[Guest]

in-addr.arpa is a standard for adding reverse lookup to the dns hierarchy.  DNS was never designed to support reverse lookups but the feature is necessary to the workings of Active Directory (notice that the ip is reversed to be in the same magnitude ordering as the name (least significant to most from left to right)).  It's an ugly hack that you will be seeing more of as AD becomes more popular.

Microsoft Rules!

gb

[Peter Motyka]

The reverse/inverse DNS spec has been around since RFC 1034 (Nov 1987).  From my review of the document, it seems the ability to map a resource back to a name was a core, but optional, feature to be supported by DNS implementations.  While Microsoft Active Directory utilizes this feature, they hardly were the first to implement the functionality.  I am unable to determine when Bind started implementing it... rest assured it was many moons before Active Directory was even a spec on the map.  When reverse DNS is configured correctly you usually end up with:

1.2.3.4 -> domain.name.com

not

1.2.3.4 -> domain.name.com.3.2.1.in-addr-arpa

It appears that reverse DNS is now working correctly with the CS hostnames.  Perhaps someone made a typo in the DNS config file.