[vox-tech] mail / DNS question

[Peter Jay Salzman]

hi all,

oddly, i'm a newbie at this sort of thing...

belial.ucdavis.edu is hosting the virtual domain roselug.org.  i think i
set up the MX records correctly.  at least, nslookup looks good:

   p@satan% nslookup 
   > set type=MX
   > roselug.org
   Server:         206.13.31.12
   Address:        206.13.31.12#53
   
   Non-authoritative answer:
   roselug.org     mail exchanger = 60 169.237.43.86.  <-- * correct IP *
   
   Authoritative answers can be found from:
   roselug.org     nameserver = A.NS.JOKER.COM.
   roselug.org     nameserver = B.NS.JOKER.COM.
   roselug.org     nameserver = C.NS.JOKER.COM.
   A.NS.JOKER.COM  internet address = 194.176.0.2
   B.NS.JOKER.COM  internet address = 194.245.101.19
   C.NS.JOKER.COM  internet address = 194.245.50.1

i reconfigured exim to include roselug.org as a local domain:

   local_domains = localhost:belial.ucdavis.edu:roselug.org

yet mail to postmaster@roselug.org is giving an error message which i
don't really understand:

   A message that you sent could not be delivered to one or more of its
   recipients. This is a permanent error. The following address(es) failed:
   
     postmaster@roselug.org
     all relevant MX records point to non-existent hosts:
     it appears that the DNS operator for this domain has installed an
     invalid MX record with an IP address instead of a domain name on the
     right hand side

ok, keep in mind i'm new at this sort of thing.   what's going wrong?
why isn't an IP address ok to use on the "right hand side"?

pete

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