Help re: MX record

[Barry Margolin]

In article <7j3n6s$nqr$1 at nnrp1.deja.com>,  <sabbah22 at my-deja.com> wrote:
>Well, for ourdomain.net, which is one of 5 files for 3 subdomains our
>DNS handles, the file contains one MX record as follows:
>
>*      IN   MX   10    Mail
>
>And then of course all the A records, like so...
>
>doodah       IN    A     xxx.xxx.xxx.xxx
>
>and so on...

That wildcard record is a stand-in for all names of the form
XXX.ourdomain.net that don't actually appear anywhere in the file.  Since
there's an explicit entry for doodah, it won't stand in for
doodah.ourdomain.net, so it needs an explicit MX record (wildcards are not
specific to a particular type).  It's also not used for the name
ourdomain.net itself.

The DNS lookup algorithm (extremely simplified) is:

1. Look for the name.
2. If the name exists, return any records of the requested type; if there
aren't any, return 0 records.
3. If the name doesn't exist, look for a wildcard that matches the name,
and return any records of the specified type.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.