What would be nice, but I am assuming nearly impossible, is to have the SMTP service listen on two ports. The list of ISP's stopping outbound port 25 is growing by leaps and bounds and has now extended to a major cable broadband provider. To give a user the option to send mail on a non-standard port would help without having to get the remaining thousands of users to change over to the non-standard port. Any suggestions?

I was thinking about doing a NAT rule on the firewall that sees a particular port bound for the mail server, say port 26, and converts it back to 25 and send it along to the mail server. I'm guessing that would solve the problem but it's a messy solution. I also don't want to try it in production.

Anyone got anything better in mind before I screw up one of my active networks?

Indeed, you need to use either a software port redirector or a NAT rule.  I'd prefer the latter.

--Sandy

------------------------------------
Sanford Whiteman, Chief Technologist
Broadleaf Systems, a division of
Cypress Integrated Systems, Inc.

Defuse Dictionary Attacks: Turn Remote Mailboxes into Aliases on your IMail MX!
  http://www.imprimia.com/products/software/freeutils/ldap2aliases/download/release/

That's what I figured. Even it it doesn't work I don't see any negative impact on the firewall at all. At first I thought it was a bit messy but the more I think about it the cleaner it actually sounds because I don't have to touch my mail servers.

Thanks