[Mailman-Users] Getting mailman to use the same smtp connection for messages sent to the same domain

[Barry A. Warsaw]

>>>>> "SW" == Simon White <simon at mtds.com> writes:

    SW> You have a point. Mailman is injecting to the MTA so if it
    SW> does connect/disconnect etc then this will affect even
    SW> Postfix. So, there does need to be a way to have Mailman open
    SW> a single connection to the server for each domain, and then do
    SW> RCPT TO: several times.

    SW> I *thought* that was what it did anyway... can anyone else
    SW> prove me wrong / right?

The chunking algorithm for sending messages to the mta is defined by
variables such as SMTP_MAX_SESSIONS_PER_CONNECTION and
SMTP_MAX_RCPTS.

The latter specifies the maximum size of the RCPT TO chunks in each
handoff to the mta.  Set it to a negative number to not chunk at all.
When chunking, Mailman first sorts by these tlds: .com, .net, .org,
.edu, .us, .ca.  Everything else goes into a separate bucket.  Yeah,
this is pretty North America-centric :/.  Note that Mailman does not
chunk based on MX or on 2nd level domain names.

SMTP_MAX_SESSIONS_PER_CONNECTION determines how many chunks it sends
down the same socket connection to the mta.  Again, a negative number
means blast all the chunks down the same connection.

-Barry