[Mailman-Users] MM FAQ/Sendmail question...

[Richard Idalski]

Q. I'm getting really terrible performance for outgoing messages. It seems
that if the MTA has trouble resolving DNS for any recipients, qrunner just
gets really slow clearing the queue. Any ideas?
A. What's likely happening is that your MTA is doing DNS resolution on
recipients for messages delivered locally (i.e. from Mailman to your MTA via
SMTPDirect.py). This is a Bad Thing. You need to turn off synchronous DNS
resolution for messages originating from the local host.

In Exim, the value to edit is receiver_verify_hosts. See README.EXIM for
details. Other MTAs have (of course) different parameters and defaults that
control this. First check the README file for your MTA and then consult your
MTA's own documentation.
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   I'm thinking this may be the case on my server, But looking through the
.cf file, and the docs that I can find I don't see a reference to this for
sendmail. Anyone else running sendmail know where I'd find this and disable
it if it is the case?

   Richard