[Mimedefang] Greylisting - Too many open connections

[Carlton Thomas]

Hi,

I have implemented greylisting in Mimedefang and all works
well until the mail server gets very busy. When it gets
busy there is a rapid increase in the number of Mimedefang,
Sendmail and MySql processes. When the sendmail connections
are examined, most of them are in the "RCPT TO" state, and
they just hang around in that state for a long time. I am
assuming that this is happening because sendmail has
rejected the message  but the client is still holding the
connection open, either to attempt immediate retries or
because it does not understand the TEMPFAIL.

The call to the greylisting code is made in Filter_Recipient
as per recommendations from various messages to this list.
I have also searched the list archive to see whether others
have had this problem but found only a couple of related
posts but no solutions.

Has anybody else managed to get sendmail to terminate the
connection when a message is tempfailed from within the
filter_recipient routine? If that is not possible, what
have others been doing to get rid of the connection in
order to minimise the number of active sendmail processes?

I did see a message in which someone stated that tempfailing
a message with the 421 code would cause sendmail to terminate
the active connection. I have tried that but it does not seem
to work for me and I have also seen others saying that it is
not possible for a milter to force sendmail to terminate a
connection.

Any help or guidance on this subject woul be most appreciated.

Regards !

--
Carlton
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