Hopefully not such a stupid question but.... What is the preferred method for adding an alternative SMTP port so that clients can use 25 or say 2525 where 25 is blocked by an ISP to send mail via our servers. My understanding is I can do it under postfix by simply adding the following to /etc/postfix/master.cf after the similar rule starting smtp. 2525 inet n - - - - smtpd OR I can redirect port 2525 to port 25 through IP tables using: iptables -t nat -A PREROUTING -p tcp --dport 2525 -j REDIRECT --to-ports 25 service iptables save (to make sure it persists on a reboot) All thoughts welcome.
