RE: Changing port for outgoing mail

Its really simple.....they do it because it's the easiest way for them to
block relaying.  Instead of actually taking the time to implement a viable
solution (which can be easily done) they take the quick and dirty approach
which is to just add a port 25 block.  Most small to medium sized ISP's do
not have the technical knowledge or willingness to take the time.

There is nothing inherently wrong with the approach, but there are far
better solutions that do not impact customers as much as the port 25 block.

We had the same problem for a long time, that is until we started using
dedicated circuits.


-----Original Message-----
From: midrange-l-bounces+dpalme=hdsmith.com@xxxxxxxxxxxx
[mailto:midrange-l-bounces+dpalme=hdsmith.com@xxxxxxxxxxxx] On Behalf Of
Scott Klement
Sent: Wednesday, November 29, 2006 3:47 PM
To: Midrange Systems Technical Discussion
Subject: Re: Changing port for outgoing mail


Hi Doug,

Why would they do that?  I thought the purpose of ISP's blocks on port 25
were to help isolate machines running rogue compromised bots spewing out
spam and sending it directly to other recipient mail servers.

I don't know why they did it.

They didn't tell me that they were going to do it, but all connections on 
that port number stopped working (including using telnet to test it) as if 
blocked by a firewall.  Switching it to a different port immediately 
solved the problem, but I didn't want to keep doing that over and over.

They wouldn't normally be listening on anything other than port 25, so 
why block 2525 and 8025.  Did you ISP actually detect you had email 
traffic on those ports and shut them off?

That's my guess -- though I don't really understand why it'd matter to 
them that I was sending it.

I've never had trouble using port 2525 with either of my ISP's in getting
mail to smtp.com's servers.

That's good, I'm glad it has worked for you. But, I'm not making this up 
-- they really blocked those ports for me!