Opening up SMTP on port 26

[teren]

Hi All,
I have a client that would like port 26 open on SMTP so that he can use my servers as his mail server since his ISP blocks port 25. Is there a simple way to do this or can somebody give me an idea? I'm really only familiar with BSD and PF, so i'm somewhat lost with IP Tables ans such
(Server is Plesk 7.5.3 Fedora Core 2)

Thanks

 

[jamesyeeoc]

Easy Alternate Port, but not port 26

If you want a really EASY and simple alternate port, you can copy and edit a single file which will allow your clients to send outgoing SMTP email on port 587. These instructions assume you are running some version/flavor of Redhat Linux.

Step 1: Duplicate the /etc/xinetd.d/smtp_psa file

cp /etc/xinetd.d/smtp_psa /etc/xinetd.d/smtp_additional

Step 2: Edit the smtp_additional file

vi /etc/xinetd.d/smtp_additional
Change the first line from 'service smtp' to 'service submission'

Step 3: Restart xinetd

killall -HUP xinetd

Step 4: Test sending email to your server on port 587 instead of port 25. Have your clients reconfigure Outlook or whatever their email client software to use port 587 instead of port 25.

I'm sure there are other ways, but I have found this to be the easiest to implement and maintain on the server. The client just reconfigures for port 587 instead of 26, either way they have to make a port change regardless.

This change has no effect on the normal port 25, so your other clients without ISP port blocking, can still use port 25.

 

[teren]

Thanks,
WIth that informail been said, for anybody else wanting to do so....all you have to do is define a new service in /etc/services and then instead of using 'submission' like above just use whatever you name the new service (ex smtp2) and you can run on whatever port you want and avoid conflictions. Thanks a lot, teamwork rocks

 

[memphishost]

Port 587

You could have used port 465 and selected SSL.

Qmail listens to both port 25 and 465.




Beats editing files.

 

[mannyd]

from the sw-soft faq

you can change it to any smtp port with this i guess, sames lines as OP, but customizing the port

http://faq.sw-soft.com/article_22_837_en.html

 

[zymsys]

I just add this to my rc.local:

/sbin/iptables  -t nat -I PREROUTING -p tcp --dport 26 -j REDIRECT --to-port 25

I'm running this way on 4 servers.