On Wed, Nov 23, 2016 at 01:53:22PM +1100, Sam Vaughan wrote: > Hi [email protected], >
Hi, > I???ve been a very happy user of OpenSMTPD for some time now, but I > encountered a DNS issue today which seems to have caused mail to be lost. > > For some reason, the primary DNS server in the data centre I'm using started > replying to lookups with REFUSED last night. As a result, smtpd couldn't > resolve destination MX addresses and emails stopped getting delivered. Many > /var/log/maillog entries started appearing along the lines of: > > smtp-out: routing: Failed to resolve MX for [blah]: Invalid domain name > smtp-out: session 0000000000000000: evpid=blah, status=PermFail, from=<>, > to=<[email protected]>, rcpt=<->, source=-, relay=bar.com, delay=0s, stat=Invalid > domain name > warn: queue: no return path! > > What surprised me about this situation was that smtpd seems to think it > successfully delivered all those messages. `smtpctl show queue` is empty and > there are no files sitting in /var/spool/smtpd, so as far as I can tell the > messages are gone. I was expecting to find them tucked away in a directory > somewhere waiting for something to be done about them. Is this expected > behaviour? > The "Invalid domain name" error will only happen when the MTA layer gets a DNS_EINVAL error which is considered unrecoverable in the sense that a similar query will result in a similar error. The question is, are there cases where error is considered unrecoverable when it really isn't the case ? I see two cases in the code where I'm unsure it's not getting this wrong so I'll check with eric@ what he thinks. > The other surprising thing to me was that the system's DNS lookups weren't > clever enough to ignore the server that was returning REFUSED and fall back > to the second DNS server listed in /etc/resolv.conf, which was still working > just fine. That's a question for a different list though. > That would be a side effect of a bug above. > OS and software versions: > > FreeBSD 10.3 > opensmtpd-5.7.3_2,1 > libasr-1.0.2 > libevent2-2.0.22_1 > Thanks for the report, we'll get back to you shortly. Could you please open a ticket on our tracker with a copy of this mail ? -- Gilles Chehade https://www.poolp.org @poolpOrg -- You received this mail because you are subscribed to [email protected] To unsubscribe, send a mail to: [email protected]
