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

Simon White simon at mtds.com
Fri Jan 31 19:26:00 CET 2003

31-Jan-03 at 13:00, Barry A. Warsaw (barry at python.org) wrote :
> The chunking algorithm for sending messages to the mta is defined by
> variables such as SMTP_MAX_SESSIONS_PER_CONNECTION and
> 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.

Chunking like this means that you're actually sending RCPT TO: based on
TLD, and then only US TLDs, right? So SMTP_MAX_RCPTS set to 50 could
mean several different second level domains in the same chunk, but for
every TLD outside the US there will be separate sessions for each mail

How about chunking something like this pseudo-code:-

split tlds into an array
for each tld in array
sort second_level_domains into unique sets
if unique set_length = 1 combine with previous 
	until set_length = SMTP_MAX_RCPTS
end if

Not exactly easy in real code, but if what you say about the algorithm
is true, then I could seriously improve performance for my lists by
doing this. Right now, my MTA takes over 3 hours to deliver the bulk of
my 12000 subscriber list (not including bounces and poor receiving
MX hosts).

Where is this done (which file) - I could have a stab at it.

|-Simon White, Internet Services Manager, Certified Check Point CCSA.
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