Routing via PPP question

[Neil Ford]

Okay, having now got the dial-in/dial-out stuff working, I need to crack
the routing set-up. Not a detailed area of expertise for me, so I thought
I'd ask in here.

Here's some Crap ASCII Art of what I'm trying to achieve;

[Lan 1]
Internet <->   gateway    <->      LAN    <->       ppp router (dial-out)
                 linux           windows             freebsd
             192.168.200.1                    192.168.200.11 (ethernet)
                                              192.168.200.12 (tun0)
                                                      ^
                                                      |
                                                      |
[Lan 2]                                              \/
Internet <->   gateway    <->      LAN    <->       ppp router (dial-in)
                 linux           windows             freebsd
             192.168.100.1                    192.168.100.11 (ethernet)
                                              192.168.100.12 (tun0)

What needs to happen is for all the workstations to treat their respective
linux boxes as their default gateways but for traffic for the other Lan
(primamrily email) to go via the shiny new PPP routers.

My prior experience tells me I need to set up routes on the two linux
boxes to say any traffic for the other LAN goes via the .11 address. What
I'm not certain about is what values for defaultrouter and what commands
in ppp.conf I need on the routers to make sure they don't get confused and
correctly route traffic.

So learned audience, what is your advice?

Neil.

-- 
Neil C. Ford
Managing Director, Yet Another Computer Solutions Company Limited
neil at yacsc.com - http://www.yacsc.com