resolving domains, with multiple domains on server?

[Brian Findlay]

I have been having some problems, related to our local ISP in town bouncing messages, and not delivering them, due to the 'from' domain (my server)'not resolving'.  This confuses me.  My DNS records with Network Solutions, are set up correctly, and the domains themselves serve just fine.  Performing a whois on any of these domains correctly points to my (single IP) server.  The general settings main domian in SIMS is set to another domain (not mine), and if I switch it, the routre doesn't recognize any addresses anymore.

Here is a snip from the sysop at the ISP, telling me what the problem is...

**** bounced message clip ****

... while talking to mail.pris.bc.ca.:
>>> MAIL From:<[EMAIL PROTECTED]> SIZE=565
<<< 451 4.1.8 <[EMAIL PROTECTED]>... Domain of sender address [EMAIL PROTECTED] does not resolve
<[EMAIL PROTECTED]>... Deferred: 451 4.1.8 <[EMAIL PROTECTED]>... Domain of sender address [EMAIL PROTECTED] does not resolve
Warning: message still undelivered after 4 hours
Will keep trying until message is 3 days old


****** end *****



***** ISP sysop reply to my inquiry *****

Here is what I get when I look you up: (more below)
--------------------------------------------------------------------
"sun:/work/users/akoppel# nslookup solutions-consulting.net
Server:  sun.pris.bc.ca
Address:  199.60.237.1

Non-authoritative answer:
Name:    solutions-consulting.net
Address:  204.244.59.132

nslookup 204.244.59.132
Server:  sun.pris.bc.ca
Address:  199.60.237.1

*** sun.pris.bc.ca can't find 204.244.59.132: Non-existent host/domain
sun:/work/users/akoppel#
----------------------------------------------------------------------------

That means that I can translate solutions-consulting.net to an address
BUT

when mail comes from 204.244.59.132, I do not know who the heck you are,
so I do not trust you, so I will not handle your mail.

Talk to the name of the person who handles your DNS resolution.. and have
him check/update his REVERSE DNS table (table.ar  as well as table.ptr).

If you share this message with you provider, he should know what I mean.

This is independent of your Whois entries.


*****  end   *****

So what does all this mean??  What is a 'REVERSE DNS' table, and where is it, and how do I update it??  I manage the DNS server for this site (MacDNS), and I looked for such a setting, but could see nothing that seemed close.