Port 25

From SuperbHosting.net Support Wiki

SMTP is the protocol used for sending mail across the internet. We provide this service as part of all shared hosting accounts; for help configuring your mail client (the program used to send/receive mail from your computer) please visit help to send and help to receive.

As the internet-wide mail systems become clogged with SPAM messages, some ISPs have begun filtering outbound traffic to port 25 on non-approved mail servers. For instance if you are a Comcast Cable subscriber, you may only be able to connect to smtp.comcast.net on the default SMTP port 25. Attempts to send mail through other servers (such as smtp.superb.net) will be outright denied.

While this is unfortunate and frustrating to users, we have provided a work-around with our mail system. Simply configure your outgoing mail server to use port 8025 and you may send mail with none of these potential issues. Here are two simple tests with telnet to demonstrate:

• First to port 25:

$ telnet smtp.superb.net 25
Trying 209.61.193.88...
Connected to smtp.superb.net.
Escape character is '^]'.
220  ESMTP
quit
221
Connection closed by foreign host.

• And one to port 8025:

$ telnet smtp.superb.net 8025
Trying 209.61.193.88...
Connected to smtp.superb.net.
Escape character is '^]'.
220 mail-relay2.dca2.superb.net ESMTP Exim 4.69 Mon, 23 Jun 2008 16:36:19 -0400
quit
221 mail-relay2.dca2.superb.net closing connection
Connection closed by foreign host.