[KLUG Members] sbc blocking port 25

[bill]

SBC DSL & dialup started blocking port 25 today, so you may not be able
to send your e-mail messages.

Tech support won't admit it unless you specifically ask them "Are you
blocking port 25?" Costing me a fair amount of time and anguish and a
second call to TS.

You can request that they unblock the port here:

http://help.sbcglobal.net/servabuse.php 

Make sure to select the drop down list under "Abuse Type" as **Opt Out
Port 25

For some odd reason, tech support wanted me to list -all- the email
servers I may send to, which is a list too big to remember (no I send no
spam).  She assured me that any server I didn't list would get blocked. 
So they'll filter port 25 only allowing listed servers?  I'll check on
that and report later.

The other thing you can do, if you have access to your sendmail servers
on linux (of course), is tweak iptables.

Let's say you want the server to use port 2525 (it will still accept
port 25), and your server ip is 12.34.56.78.  you can add this line: 

-A PREROUTING -p tcp -m tcp --dport 2525 -j DNAT --to-destination
12.34.56.78:25

hth,

bill