I'm prepping for an ISP migration and I wanted to setup the reverse DNS entries. When I went to do that I found an inconsistency in how they were setup for the 2 different mail servers. On one server, the servername as defined in the FQDN setting and the PTR record match, which is what I would expect. On the other server, the PTR record doesn't match any FQDN I can find anywhere in the configuration. (I do not receive any SMTP 550 messages, so somehow we're still OK as far as servers that check the reverse DNS entry)
So when a Domino server sends an email to an outside SMTP server, what defines which name it provides as its own connecting hostname?