Hello,

I've done some searching in the groups, but I'd like to pose a specific
scenario. We are getting these errors:

#4.7.1 smtp;450 4.7.1 Client host rejected: cannot find your reverse
hostname,


This is the situation. Our domain name is registered with network
solutions. Our website is hosted with Yahoo on a business account.
Yahoo used to host our email as well. Recently we put in a local SBS
2003 server to host our Exchange locally. Originally our Network
solutions account had all DNS pointing to Yahoo's name servers, as it
should have. We wanted to switch the MX record to point to our static
IP on our T-1 for our new server. However, we can't have the www
address point to a single IP with Yahoo. Yahoo requires that we just
redirect Network Solutions DNS to them. So we reverted all DNS back to
Yahoo.

Now Yahoo has static entries for www and mail .domain.com pointing to
internal yahoo server, which we can't change. We added a record for
our mail server: server.domain.com and pointed it to our static
external IP address. We also created an MX record for
server.domain.com. Email started flowing in as expected.

However now some email systems, most notably AOL and Comcast, are
resolving our name it seems. We are getting the message I posted
above. Many of the postings I've read say that we need to add a PTR
record for our mail server. Is that on our local internal DNS or on an
external? If it is external DNS, then whos? Our ISP (AT&T) or on
Yahoo?

Thank you,
Brandon Riffel