Use AWS EC2 to redirect incoming mail

Question

Is it possible to setup an EC2 instance as a mail server and relay incoming mail to my domain to my in-house server on a different port than port 25?

Right now I use rollernet.us for this. Which works fine but I wanted to just see if I could replicate the same functionality but save a few pennies. My server sits behind my router which is running off of Comcast so port 25 is a no go. I'm using Comcast's relay for outgoing mail but will switch to SES when I can figure out how to manage incoming messages.

I'm not sure I have the lingo correct either which may be why I can't find any info on this. Is it just as simple as installing postfix and setting the relayhost to my desired domain with my desired port?

Answer 1

You can do that. Use your ec2 instance as the MX server and disable local delivery on that. Set your domain as relay_domain and set a custom transport to your server behind router, running on port other than 25.