Email Delivery Question

Question

This question comes on the heels of the question asked here.

The email that comes from our web server comes from an IP address that is different than that for the Exchange server. Is this okay if the SPF and Domain keys are setup properly?

Answer 1

Short answer: Yes

Answer 2

It should just fine. However some spam filters will do a reverse lookup on the originating IP address and see if it's assigned to the domain name the email claims to be from, and some may check to see if the IP is an actual MX for the domain.

So the downside is that some recipients may never get the email, and you may not know about it for a long time. I'd suggest routing your mail through an established MX rather than having a webserver do it directly (there are some security implications there too).