SMTP on Multiple Ports?
How would I go about setting Zimbra to listen on 2 ports for SMTP? I have one user's ISP that blocks outbound port 25. I would like to configure my server so some users could select a non standard port for SMTP. I have read several posts about using smart relays when users have their Zimbra Servers on ISP's that blocks port 25, but my situation is a little different since it's just the user's ISP, not the server's ISP.
Or, edit master.cf to add an smptd on another port (don't remember the exact syntax - look it up):
myhostname:4000 ... smtpd
Please test to make sure mail gets routed through amavisd = if not you might have to configure the content_filter option on above line (though I doubt you need to.)
Please post your solution - for the record, thx.
We may not preserve master.cf across upgrades - so lookout for that.
Port fowarding via iptables seemed to do the trick for me.
iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 465 -j REDIRECT --to-port 25