[Mailman-Users] Lists stopped for dns problems ?
Nigel.Metheringham at dev.InTechnology.co.uk
Mon Mar 10 12:15:45 CET 2003
On Mon, 2003-03-10 at 10:32, DOMA Peter wrote:
> Both lists stopped, the qrunner process got locked, the posts come in,
> but does not go out.
> I have the smtp-failure log full of these:
> 451 email.address at here (Cannot check <email.adress at here> at this time -
> please try later)
> I read the exim-users archive, and finally found that it's often caused
> by dns problems.
Ideally you fix the DNS problems if this is a general problem other than
with a number of specific addresses.
However there are a set of approaches for this as a general problem:-
1. Run a local caching DNS server, especially if you are more than
a 100Mbit link from whatever resolver you use. Make sure the
MTA is using that resolver. djb's dnscache works OK for this -
2. Don't do DNS lookup (ie recipient verification) in the MTA for
Mailman traffic. Instead let the MTA sort it out and deal with
the bounces. For exim do something like:-
"receiver_verify_hosts = !127.0.0.1/8:0.0.0.0/0" to prevent
verifies on mail recipients from a local Mailman install.
Either of these will help, although you main answer - and a way of
speeding things up for mailman submission is to do (2). (1) will
generally speed the MTA.
This stuff *is* in the FAQ.
[OK, I admit I have slightly modified the first 2 of these in the light
of this question, and although I am sure the stuff about DNS caches is
in there somewhere I have explicitly created the 3rd FAQ entry there on
DNS cache usage. If people hate those answers please fix them!]
[ Nigel Metheringham Nigel.Metheringham at InTechnology.co.uk ]
[ - Comments in this message are my own and not ITO opinion/policy - ]
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