[ale] ip route and using linux as a "real" router

[Grant Robertson]

I'm very confused, so if I'm way off base in anything I write, forgive
me and correct me.

I have a /28 network that I need to route through/using a 2.2 kernel
machine. The machine that will act as a router has a main ip of
x.x.67.227, and the subnet I'm trying to route is x.x.72.208/28
(addresses 209-215).

I thought if I added x.x.72.209 to the "router" machine, and then
modified my route table that it would pass the packets as I expected..

'ip route add x.x.72.208/28 via x.x.72.209'

That command succeeds, and indeed the route table then shows

x.x.72.208/28 via x.x.72.209

but trying to ping x.x.72.210 (the only machine on the new network so
far) from outside results in

Reply from x.x.67.227: Destination host unreachable.

if I ping that .210 machine from the router, it works. (with or
without the route line.. )

I've tried in vein to search for info on ip route, and I find plenty
but, nothing that I've been able to really apply. It's either far to
simple, or far to complex..

Can anyone tell me what I might be doing wrong? Or point me to a doc
that I should be reading/folowing?

Many thanks.
-G