Advanced routing question

[Haim Ashkenazi <haim@babysnakes.org>]

Hi

I'm trying to combine 2 linux firewalls/routers together. the final host 
should have the following ports:

	1. eth0 - 256kbps frame relay.
	2. ppp0 (via eth1) - pppoe adsl with dhcp.
	3. eth2-3 - 2 DMZ's.
	4. eth4 - localnet.

The default route is ppp0.

Here's the problem: If I'll connect to the firewall from the internet through 
eth0 (or even connect to the dmz through the firewall's eth0) wouldn't it try 
to respond through ppp0 (the default gateway) which will make the connection 
impossible? 

Bye
-- 
Haim