I don’t know enough about the mechanics of MX and SMTP, but for those with static IPs at home, could there be an option to fall back to that when the AWS servers go wonky or have deliverability issues… or even an option to make the local IP the primary? Maybe something with the MX record weighting?
For the sake of argument, lets say you can do this. In order to make it work the following would have to happen:
- 2 records for DNS would need to be updated with the new IP information (forward and reverse records for <mail.yourdomain.tld>
- other mail servers need to recognize this change (depending on record TTL it could be 5m to 24hr+)
- personal firewall/NAT boxes would need to be reconfigured to allow incoming connections on 25, 465, 587, 993, 80, 443, and any other additional ports for services to become accessible to the internet (not all home ISPs allow running servers).
when you’re done, all this would be undone.
I would not recommend this for anybody who isn’t already comfortable running a UNIX server and securing/protecting it from the internet. Too many ways for things to go sideways and you end up with naughty people using your equipment for things you didn’t intend.