try doing a reverse DNS lookup on the mail server.
I use a tool called netscan tools to query DNS for domains.
The rejected server probably has a problem with their DNS entries. Either MX is wrong or A record is wrong. I see this ever so often. A lot of folks think setting up a mail server is a walk in the park and don't learn the proper way to do it.
If this is the case and the mail admin is reasonable, he should appreciate your input. |