It was very elementary... my inability to read. The pref 0 server was available, but rejecting because of an rDNS issue. pref 10 was unreachable due to being ipv6-only.
Apparently, Jared's servers were among the very few servers (only one that I'm aware of) that actually did an rDNS check before accepting email. I migrated my DNS to a hidden master setup years ago. Well, all of my forward lookup zones. Apparently, I forgot to point ARIN to my new setup, and when I powered off the old iron, the server that ARIN knew of went offline, taking down my rDNS. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP ----- Original Message ----- From: "Mike Hammett via mailop" <[email protected]> To: "mailop" <[email protected]> Sent: Thursday, February 13, 2025 4:54:13 PM Subject: [mailop] Understanding MX Preference This seems a bit elementary, but it's not working as I'd expect. I'm trying to send an email to a well-known mailing list (voiceops). My mail server (Proxmox Mail Gateway) seems to be skipping over the server at preference 0 and is trying to send to preference 10. My issue is that the mail server at preference 0 has both IPv4 and IPv6 addresses, but the one at preference 10 only has an IPv6. I am IPv4-only, so we can't communicate. I already have a relationship with Jared, so I can work out the technical aspects of his free and appreciated service. I'm trying to figure out why I would have skipped over the supposedly preferred server to talk to the less preferred server. ----- Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop _______________________________________________ mailop mailing list [email protected] https://list.mailop.org/listinfo/mailop
