[SOLVED] Additional internal SMTP port

[Bento]

Hello all,

We have been using Proxmox Mail Gateway for several years now and are very happy with the product and wish to thank all the team for making it possible.

Our setup is the standard setup with

External SMTP port: 25
Internal SMTP port: 26

All of this has been working fine for years, and we have lots of VMs/equipment/applications setup to use the internal SMTP port of 26. However we have obtained a bit of equipment that for some silly reason does not allow us to specify port 26 for outgoing mail. (The only ports it lets you set are 25, 465, 587, 2525, 5000 to 32768).

My question, is am I able to add an additional Internal SMTP port as well as the current port 26? So the new item of equipment will work on this alternate port, but all existing systems that are currently set up will carry on using port 26?

So the internal SMTP port would be set to port 26 and 2525 for example.

Many thanks in advance for any help.

Ben

 

[treloskilo]

You can redirect the port with iptables
iptables -A PREROUTING -d (ip address of the pmg) -i (name of interface) -p tcp -m tcp --dport 2525 -j REDIRECT --to-ports 26

hope it will work

 

[Bento]

iptables -A PREROUTING -d (ip address of the pmg) -i (name of interface) -p tcp -m tcp --dport 2525 -j REDIRECT --to-ports 26

Hi treloskilo,

That's a brilliant idea, thank you so much! I've implemented this and it is working well. I had to modify the command slightly:

iptables -t nat -A PREROUTING -d <IP> -i eth0 -p tcp --dport 2525 -j REDIRECT --to-port 26

Thanks for your help it's really appreciated!