On Tue, Oct 21, 2025 at 04:59:20PM +0200, Antonin Verrier via Postfix-users wrote:
> Le 21 octobre 2025 08:52:23 GMT+02:00, Antonin Verrier via Postfix-users > <[email protected]> a écrit : > >See this log line for example: > > > >2025-10-20T00:27:12.626227+02:00 mail postfix/mx/smtpd[226824]: warning: > >Unable to look up MX host irondelle.o2switch.net for Sender address > >[email protected]: Name or service not known > > I've just realized something... If I have the above line in my logs, > doesn't that mean the A lookup for the MX is happening already anyway > ? > > I have also check_sender_mx_access restriction in place so maybe it comes > from there. Yes, it appears that check_sender_mx_access performs table lookups for each MX host, not just by name, but also by its IP addresses. FWIW, I don't think this is a good idea, I would have limited the lookup keys to just the hostnames which are returned in a single DNS query. Similar behaviour is shared with check_sender_ns_access and related restrictions. -- Viktor. 🇺🇦 Слава Україні! _______________________________________________ Postfix-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
