search for: old_mail_server_ip

Hi, I am trying to set up a firewall rule so calls to old_mailserver:25 get redirected to localhost:25. I have seen quite a few rules and none seem to work. I have tried with the firewall enabled (configured to allow smtp) and disabled, but it doesn't seem to make a difference. One of the commands I have been using is: /sbin/iptables -t nat -I PREROUTING -p tcp -d old_mailserver_ip/32