How to selectivey route messages

I currently have my dialup connection to my ISP as a gateway.

I would like to have two gateways; one the dialup (on ppp0) and one on ethernet (eth1). Now with my simple setup, I could make either one the gateway, but what I want is for everything to go to the eth1 gateway except for those to ports ssh(22), smtp(25) and perhaps domain(53).

This is because I want to use Verison's FiOS (fibre optic to the home) Internet service, but they allow NO servers. I am not sure if they consider any of these to be servers, but they probably do, so I guess I will want to keep my old ISP who gives me a cheap static IP address (Verizon wants $40-month).

So how do I select the input and output interface for a message based on the port?

As a second question, how do I get Linux (I have Red Hat Enterprise Linux 3) to work with Verizon's FiOS when Verizon claims that Linux is not supported. Their service seems to have a box on the side of the house that converts the fibre-optic signals into CAT5 wire for data and twisted pair the audio signals. The CAT5 wire then goes to a special router (4 output ports) that is like a switch, but has Verizon diagnostic software in it) and then to the computer(s). I suppose I must set up to run DHCP on that interface instead of a static IP address for my machine. But what else? They allude to software on my machine (that they say can be either Windows or MacIntosh). Is that software just useless candy, or is it actually needed for the service?

I.e., has anyone already done this?

-- .~. Jean-David Beyer Registered Linux User 85642. V PGP-Key: 9A2FC99A Registered Machine 241939. ^^-^^ 14:25:00 up 10 days, 55 min, 4 users, load average: 4.10, 4.21, 4.14