I host my stalwart-instance behind a Caddy reverse proxy for HTTPS (stalwart listener on port 10443) and use automatic DNS management. This creates entries like this in my zone:
_jmap._tcp IN SRV 0 1 10443 mail.magahugu.ch.
which is clearly wrong: it should be the default HTTPS port 443.
Please add an option in Network/Services/Advertised Services to override the ports.
Stalwart v0.16.8 github build, bare metal on Arch Linux
Unfortunately this is out of scope as the PACC standard will only accept the IETF registered ports. You need to switch to manual DNS management if you want to use a different SRV port.
exactly: I want the SRV entry to be 443, not 10443. The 10443 comes from the fact that I use a reverse proxy in front of stalwart, which serves HTTPS on 10443.
The advertised SRV port for _jmap._tcp (and the CalDAV/CardDAV ones) is
fixed at 443 in the record generator, not taken from your listener port, so on a current build the auto-DNS output should already read 443 rather than 10443. The 10443 you’re seeing looks like a leftover record from an older version: a changed port doesn’t get auto-removed from your zone.
Can you re-generate the records on your current version and check the _jmap._tcp entry again? If it’s freshly generated as 10443 I’d want to see your build version, because that’s not what the generator should emit; if it’s a stale record, deleting it and re-publishing should leave you with the 443 entry you want.