sendmail AAAA woe

Thursday, 3. 11. 2005  –  Category: all, sw

In the normal run of things, the moment I want a host’s involvment with mail to be anything more complicated than just sending it I replace sendmail with exim.

Today’s struggle revealed that even setting a ‘smarthost’ (what everyone else calls ‘relays’) can be too complicated. Not entirely sendmail’s fault though, a Win2k server is serving duff AAAA records. Sendmail likes to make loads of name service lookups, and just one of these duff records will result in it sulking:
Nov  3 07:00:37 dave sm-mta[33084]: j9T7biPo056996: to=admin@zzz.co.uk, delay=4+23:22:52, xdelay=00:00:00, mailer=relay, pri=22441893, relay=budd.xxx.yyy.co.uk., dsn=4.0.0, stat=Deferred: Name server: budd.xxx.yyy.co.uk.: host name lookup failure

Now, there isn’t an AAAA record for this machine; but when sendmail queries for it, it reports SERVFAIL, whereas if I dig(1) for it, i get the correct null reply with NOERROR. Even setting WorkAroundBrokenAAAA doesn’t change this.

This seems to be the same problem as here.

I spent about an hour of this. Gah. Seems I’ll be installing exim every time from now on…

Anyway – debug sendmail name resolution over a queue run with
sendmail -d8.20 -qf

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