My fallback is just Postfix running on some VM's DNS servers that writes all email sent to it into one text file. It acts as a tarpit for spammers that look fo

My fallback is just Postfix running on some VM's DNS servers that writes all email sent to it into one text file. It acts as a tarpit for spammers that look for open relays. I also point MX for a handful of my domains to those VM's and I list secondary email canary addresses for those domains as a fallback. The VM's are spread across multiple VPS providers in the event that one of them has an outage.