[Mailman-Users] large list = very slow network

[John Meier]

Hi all-

Pretty new to mailman, and have an "announcement only"  list set up for a
client.  It's been working great for months - they send to 300 - 400 members
a day.  A couple of days ago, they uploaded 50,000 email addresses and sent
out a post.  It brought our T1 to a crawl.  I'd like to avoid this in the
future.  Here's the specs:

mailman + postfix on a compaq dl380 with 2 800 Mhz P3 and 1.5 gig RAM Redhat
4 ES (or AS - can't remember at this point).  resolv.conf points to the
provider's DNS.
We're on a T1 that is shared between two networks - our production and our
office network (192.168.170.  vs. 192.168.160.)  This machine is in our
office network and a couple of folks was pissed when the 50K mailing went
out ;)

The list server and postfix are pretty much out of the box - following the
Mailman setup for postfix.  The postfix MTA also does mail for a different
client (domain), but I'm not doing Mailman/postfix/virtual domains.  The
other client just has 5 local mailboxes - not much volume at all.

I've been reading up on performance tweaking in the mailman FAQ and was
wondering where I should concentrate my efforts to avoid the listserver
saturating my line.  I'm thinking a local dns cache on the box would be
good, but have seen anything that directly addresses how to "slow" the
system down
 to avoid cramming the network.