On 2021-08-18 Marc Haber <mh+debian-packa...@zugschlus.de> wrote: > Package: exim4-config > Version: 4.94.2-2~zg100+3 > Severity: normal
> Hi, > I am not sure whether this is an actual bug. I have observed this > behaviod on an exim that is backup MX for domain.example. The MX records > are like: > domain.example mail is handled by 0 mx.domain.example. > domain.example mail is handled by 10 myexim.otherdomain.example. > Both hosts have both IPv4 and IPv6 addresses in DNS; the local resolver > on myexim.otherdomain.example resolves its own host name to 127.0.1.1 by > virtue of the normal Debian /etc/hosts file. > [36/5023]mh@q:~ $ sudo exim -bt lists@domain.example > R: domain_literal for lists@domain.example > R: dnslookup_relay_to_domains for lists@domain.example > lists@domain.example > router = dnslookup_relay_to_domains, transport = remote_smtp > host mx.domain.example [IPv6 address] MX=0 > host mx.domain.example [IPv4 address] MX=0 > host myexim.otherdomain.example [127.0.1.1] > MX=10 > [37/5024]mh@q:~ $ > If mx.domain.example refuses mail, the local exim happily delivers to itself, > causing a loop: > 2021-08-18 08:06:15 1mGEiM-00089y-Vx <= > linux-staging+bounces-5545-lists=domain.exam...@lists.linux.dev H=localhost > (myexim.otherdomin.example) [127.0.0.1] P=esmtps > X=TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256 CV=no K > S=14699 id=<snip> [...] > Or is exim supposed to never relay to itself automatically? If that is the > case, more debugging is needed to find out why this happens here. Advice > appreciated. Hello Marc, https://www.exim.org/exim-html-current/doc/html/spec_html/ch-the_dnslookup_router.html says: | Unless they have the highest priority (lowest MX value), MX records that | point to the local host, or to any host name that matches | hosts_treat_as_local, are discarded, together with any other MX records | of equal or lower priority. | | If the host pointed to by the highest priority MX record, or looked up | as an address record, is the local host, or matches | hosts_treat_as_local, what happens is controlled by the generic self | option. (and self= defaults to "freeze") According to chapter 3, »8. Recognizing the local host« exim uses the local_interfaces setting (unless it is 0.0.0.0 or ::0) to recognize the local host. - Are you setting it? cu Andreas -- `What a good friend you are to him, Dr. Maturin. His other friends are so grateful to you.' `I sew his ears on from time to time, sure'
