I have a user on my Ubuntu 18.04 MiaB on IPv4/IPv6 behind pfSense firewall which is behind Comcast router/modem. I have a filter in the user’s account to forward to my old email server (my list server is too old to log into MiaB and get email so I need to continue using my old email server for mailing lists).
Here is the error message in mail.log
Dec 22 22:11:33 mail postfix/smtp: 610ABF60698: email@example.com, relay=none, delay=0.13, delays=0.06/0.03/0.04/0, dsn=5.4.4, status=bounced (Host or domain name not found. Name service error for name=list.server.pminj.org type=AAAA: Host not found)
Why is it not dropping to IPv4 to redirect the email?
So I can send an email using an account on the MiaB to my email server to one of my work domains. I can’t send to the domain that MiaB is hosting but I am using a subdomain (for which I have the MX record and the A record set correctly in the DNS pointing to the old server).
MiaB is mail.server.pminj.org and is also mail.pminj.org but list.pminj.org is pointing to my old server.
So my theory is that the issue is that since the @ MX record has an IPv6 address for some reason MiaB won’t check for the IPv4 address despite no AAAA record for the old email server.
So going on my own theory, I added custom DNS entries on the MiaB for the list.server.pminj.org & list.pminj.org sub-domains (I add the two MX records and the required A record the machine). It worked.
So my theory is modified…since MiaB is thinking it is hosting the DNS it wasn’t looking to the external DNS for the IP address. So I am going to second a feature request I saw in one of the hundred of threads I saw while I was trying to read every thread here…some indicator that we can check to tell MiaB it is hosting the DNS for a domain or not. And logically another flag for indicating to MiaB whether it is hosting the web site or not. And the Status Checks should honor these flags as well.