Changing Outgoing Mail Port

[Fred K. Abell Jr._1]

I desire to have my workstation send an email to my email account on the mail server, but there is an egress filter on the router blocking port 25. How do I change email to go through a different port? This workstation will not be getting any emails, I only want to send.

Fred Abell

[Steven E. Protter · Accepted solution]

Shalom,

sendmail can be modified in sendmail.cf to send outbound mail on another port.

This will do absolutely no good as no good.
servers will be listening for mail on any port other than port 25.

The solution is an smtp gateway needs to be used.

in sendmail.cf
DSgatewayserver
or
DS
[192.168.0.10]

where the numeric ip address is the address of the relay server.

Microsoft exchange servers can be configured to relay mail but you will have to convince the administrator to do this for you.

SEP

[Reshma Malusare]

Hi Fred,
According to me modification of sendmail.cf will solve your problem.
The /etc/mail/sendmail.cf file that is installed with the sendmail.The default configuration file is located in /usr/newconfig/etc/mail/sendmail.cf and is installed in /etc/mail/sendmail.cf.
Then stop & start the sendmail daemon.

Please Read following document for more information:
http://docs.hp.com/en/B2355-90685/ch04s06.html#ccieachj

[Court Campbell]

Fred,

SMTP servers listen on port 25 by default. I have never known this to be different. What I do not understand is why you cannot send yourself and e-mail. The router may be blocking out going mail from any machine other than your company e-mail server. This is usually done to keep spam, etc. from being send from compromised computers. You might ask your e-mail admin which server is the smtp server. Then you could set it up in your sendmail file as a smarthost.

[Fred K. Abell Jr._1]

My purpose was to get around the egress filter on the subnet router. I wanted to send IDS alerts to my email, and the email server is on another subnet. I see that modifying the outgoing port will be useless without a relay to bounce the mail to the correct port. Thanks all.

Fred

[Court Campbell]

Fred,

If it is important for you to receive these alerts you need to get with the network admin and even your boss and express this need. Hopefully they will be willing to make changes on the filter to allow traffic on port 25 from that particular machine.