On Mon, 23 Mar 2026 16:32:36 +0100 Matus UHLAR - fantomas via Postfix-users <[email protected]> wrote:
> When the first return failures - but when the first address is unreachable, > it takes a while to timeout, which will users consider "slow" and will > complain about that. That depends on the client. > Btw, which IMAP/SMTP client will retry another IP if one returns failure? All of them should. Personally I only tested Sylpheed MUA. I used it for years and quite like its lightweight design. I have imap.example.com record that points to 2 IP addresses. I powered off 10.0.5.52 to test failure modes: $ dig imap.example.com +short 10.0.5.51 10.0.5.52 $ ping -c 1 10.0.5.51 PING 10.0.5.51 (10.0.5.51) 56(84) bytes of data. 64 bytes from 10.0.5.51: icmp_seq=1 ttl=255 time=0.355 ms $ ping -c 1 10.0.5.52 PING 10.0.5.52 (10.0.5.52) 56(84) bytes of data. >From 10.0.0.6 icmp_seq=1 Destination Host Unreachable When Sylpheed is connecting to imap.example.com and the powered off host (10.0.5.52) happens to be the first IP address returned by DNS resolver, I only notice a 5 second wait. There are no error messages about the unreachable hosts. This is how all good clients should behave. _______________________________________________ Postfix-users mailing list -- [email protected] To unsubscribe send an email to [email protected]
