16 messages in net.sourceforge.lists.courier-users[courier-users] Re: DNS lookups behav...
FromSent OnAttachments
Tim HoskingSep 6, 2001 6:55 am 
Sam VarshavchikSep 6, 2001 2:49 pm 
Tim HoskingSep 6, 2001 3:23 pm 
Sam VarshavchikSep 6, 2001 3:50 pm 
Tim HoskingSep 7, 2001 8:44 am 
Sam VarshavchikSep 7, 2001 5:43 pm 
Tim HoskingSep 10, 2001 6:56 am 
Sam VarshavchikSep 10, 2001 3:18 pm 
Tim HoskingSep 11, 2001 6:34 am 
Sam VarshavchikSep 11, 2001 10:51 am 
Tim HoskingSep 12, 2001 4:48 am 
Tim HoskingNov 15, 2001 10:31 am 
Sam VarshavchikNov 15, 2001 2:43 pm 
Tim HoskingNov 15, 2001 5:40 pm 
Sam VarshavchikNov 15, 2001 6:16 pm 
Tim HoskingNov 17, 2001 3:13 pm 
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Subject:[courier-users] Re: DNS lookups behaving strangelyActions...
From:Sam Varshavchik (mrs@courier-mta.com)
Date:Sep 6, 2001 2:49:40 pm
List:net.sourceforge.lists.courier-users

Tim Hosking writes:

OK.

I'll try to explain this as clearly as possible, so please bear with me.

My Linux box runs Courier and Bind (and lots of other stuff). In the DNS it is listed as the primary MX for trhosking.com. Until yesterday, the secondary MX pointed at an offsite Linux box which had no active secondary DNS.

Anyway, for whatever reason, the machine acting as the secondary MX was offline for a short period. When I tried to send mail though mail.trhosking.com to whoe@trhosking.com, courieresmtpd failed with the following error: (sorry about the wrapping).

----------- Sep 4 12:39:16 OldPeculier courieresmtpd: error,relay=::ffff:209.87.228.98,from=<ti@trhosking.com>: 417 DNS lookup failure: trhosking.com. Try again later.

-----------

Bearing in mind that the primary DNS for trhosking.com was alive and well and running on the local machine, why should it have failed? When the secondary MX came back online shortly afterwards, everything worked fine.

Surely it should only look for the secondary MX if the primary is unavailable?

This error indicates something else. The error means that Courier did not receive a response of any kind from the DNS server. Check your /etc/resolv.conf, and make sure that the listed nameservers in there are correct. Courier uses the nameservers listed in /etc/resolv.conf to resolve DNS. Even if a nameserver is running on the same machine, it must be listed in /etc/resolv.conf.

-- Sam