On Sat, Nov 08, 2025 at 07:12:39PM -0800, Ian Z via Exim-users wrote: > > Now I'm a bit surprised that exim would prefer IPv6, fail, and not > > fallback to IPv4 > > > Also, if interface is set to an IPv4 address in the config, would > > would exim even try to do IPv6 and then, indeed, fail? > > Your system may not be configured for IPv6 ... except for DNS. Correct. It wasn't before its hardware/OS upgrade either. I do need to look into that eventually, but it hasn't happened yet.
> Have you made the suggested change in /etc/gai.conf for hosts that > prefer IPv4? To be honest I'm not going to start maintaining a list of such hosts, especially since I need to be in d+all mode to even get their names/IPs to start with. This is not scalable or reasonable, and a bad baid aid at most. The 2 reasonable options are 1) fully configure IPv6 on that host, which really is the path formward 2) turn off IPv6 in exim4. The only thing that exim4 may be doing wrong is sending Email does properly fall back from IPv6 to IPv4 without issues. But SMTP callouts seem to take some shortcut and do not fallback from v6 to v4 if v6 fails. This is really what caught me by surprise. If regular Email was also failing, it would have been easier to catch. I'm not sure if this can be considered a bug in exim 4.98, but mentioning it just in case. Thanks for the help, Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Home page: http://marc.merlins.org/ | PGP 7F55D5F27AAF9D08 -- ## subscription configuration (requires account): ## https://lists.exim.org/mailman3/postorius/lists/exim-users.lists.exim.org/ ## unsubscribe (doesn't require an account): ## [email protected] ## Exim details at http://www.exim.org/ ## Please use the Wiki with this list - http://wiki.exim.org/
