Mail Submission Protocol

Wed Apr 21 13:49:07 UTC 2010

Hello all,

At our ISP operation, we are seeing increasing levels of traffic in our
outgoing MTA's, presumably due to spammers abusing some of our subscribers'
accounts. In fact, we are seeing connections from IPs outside of our network
as many as ten times of that from inside IPs. Probably all of our customers
are travelling abroad and sending back a lot of postcards, but just in
case... ;-)

So we are considering ways to further filter this traffic. We are evaluating
implementation of MSA through port 587. However, we never did this and would
like to know of others more knowledgeable of their experiences. The question
is what best practices and stories do you guys have to share in this regard.
Also please let me know if you need additional detail.

thanks in advance,
cl.