[Mailman-Users] Mailman + Postfix - Too Many Connections

[Alice Kaerast]

On Thu, 07 May 2009 15:42:45 +1000
"Lie, Jafaruddin" <lie at acer.edu.au> wrote:

> This is not strictly a mailman issue, but I would assume some people
> here would have encountered this issue.
> 
> We sent out mailing lists to schools here in Australia, and recently
> we've been getting "Too Many Connections #421" errors from them.
> Mails destined to gmail or hotmail are OK.
> 
> We're not trying to spam them (we have put links to unsubscribe, etc)
> but since the same mail server hosts emails for almost all the school
> domains, it's not liking us. I've set postfix variable of
> default_destination_recipient_limit to 15, still not liking it.
> 
> Any suggestions on rate-limiting on Postfix / mailman??

It's horrible trying to debug things like this, working out what their
limit is and then sticking to it.  Try asking them what limits they are
imposing (or search Google to see if anybody else has researched it)
and then set them.

It isn't Mailman you want to be looking at, it is Postfix.  I'm not a
Postfix expert but <http://www.postfix.org/postconf.5.html> has lots of
settings you could be looking at such as
default_destination_concurrency_limit,
default_destination_recipient_limit, default_recipient_limit.

See also
<http://dev.riseup.net/grimoire/mail/postfix/dedicated-transport/>
if you want to be limiting for just a handful of destinations.

-- 
Alice