DNS on Windows Server 2003, 3rd Edition

Changing the Origin in a Datafile

The default origin for a DNS datafile is just the domain name of the zone. The origin is a domain name that is appended automatically to all names not ending in a dot. This origin can be changed within the zone datafile using $ORIGIN, which must be followed by a domain name. (Don’t forget the trailing dot if you give the full domain name!) From that point in the file on, the new origin will be appended to all names not ending in a dot.

If we didn’t have the DNS console to make changes and had to edit files by hand, we’d run into times when $ORIGIN would save us some work. For example, if your name server were responsible for a number of subdomains, you could use the $ORIGIN entry to reset the origin and simplify the files. For example, from the movie.edu zone datafile:

$ORIGIN classics.movie.edu. 
maltese       IN  A  192.253.253.100 
casablanca    IN  A  192.253.253.101

$ORIGIN comedy.movie.edu. 
mash          IN  A  192.253.253.200 
twins         IN  A  192.253.253.201

We’ll discuss creating subdomains in Chapter 10.