Karl Schmidt wrote: > Somehow I think my point was missed - the real reason they were blocking is
> that the sending server doesn't have port 25 open to the public! The sending
> server was also not the MX server. (The helo was/is just fine - they just can't
> get it except from our MX listed server).
Sorry, I can't parse that.
You've given them a HELO by initiating an SMTP connection to them. They
have it from that point; I don't see how they "can't get it".
Does the HELO you send have an rDNS? Does a forward lookup on the
result of the reverse lookup match?
> They are not doing a callback based
> on the MX record, but instead on the sending IP.