Hi,

I'm sorry, but this will be a bit vague. And yes, I've tried looking this up in the right RFC's, but...

I wonder what happens if email gets delivered to a machine (eg, the best priority MX record for a domain) with the smtp port open, but the machine rejects messages for that domain.

Does the sending server (assuming it follows the standards) retry with a lower priority MX server? (as it does with a port reject) Or does it assume the mail is "not wanted" and quit trying to send?

My situation: I'm currently hosting mail for my domain trough my dynamic dns account (with dynamic ip), so what happens if the dynamic hostname doesn't point to my machine, but to someone else who does accept smtp connections but rejects the mail?

(I realise someone could theoretically be running an open relay or a blackhole, and then email to my domain would be lost, but that'd require an unlikely simultanious occurance of events)