We are trying to set up two PPP's, to two different ISP's, one of which (ppp1) will carry all of our LAN's internet mail (smtp -25, pop3 -110) traffic, and the other (ppp0) the balance of our internet traffic (http, ftp, etc.)
The mail (ppp1) connection is full time, the "rest" (ppp0) is dial-on-demand (diald, already working fine).
We already have the "mail only" IPForwarding rules sorted, so we are looking for the "exclude mail" rules, as well as the rules to ensure that traffic is routed to the correct port.
An extra problem is that it seems that if you have ppp0, then ppp1, both are recognised, but if you only start ppp1, the system thinks it is ppp0!
We are running RH5.0, 486/66, 24Mb, 1 x NE2000 (eth0), and 2 x modems.