I need to send the packets of specific port to different gateway. This is the situation:
The server has different services, like http, dns, and mail (smtp,pop,imap), and it has two gateways.
eth2: Gateway1 (Default gw)
All the services run ok on the default gw (eth2), but I need to send all the packets that the server generate to send email (dest port 25) to go out to the Gateway2 (ppp0).
It isn´t possible with prerouting because there are packets that are locally generated.