Static route between two machines.

[David Fuchs]

Hello,

	In a little test scenario to learn more about routing, I've come up 
with the folling setup consisting of two machines, directly connected 
via two separate interfaces on each machine:

	172.16.100.10 <------->	172.16.100.25
	(fxp0)			(ed0)
	Host ABC		Host XYZ
	(fxp1)			(ed1)
	192.168.100.10 <------>	192.168.100.25
			

	What I'm trying to do, is force all network traffic through the 
interfaces on the 172.16.100/24 subnet, as if the link between the two 
hosts over the 192.168.100/24 subnet did not exist.  For example, if I 
were logged into host ABC and attempted to ping 192.168.100.25, I would 
like the echo request to be sent via fxp0 (and have the reply come back 
on fxp0, of course).

	I've tried doing this by setting up static routes on each host such as:

	Host ABC: route add -host 192.168.100.25 -interface fxp0			Host XYZ: 
route add -host 192.168.100.10 -interface ed0

	The commands succeed, but the resulting routes don't work as I 
expected.  If I tell tcpdump to listen for ICMP and try pinging 
192.168.100.25 from host ABC, tcpdump shows that fxp0 (172.16.100.10) 
did, in fact, receive an echo request, but ed0 on the other end (also 
running tcpdump) never picks up that request.

	I'm not sure if the traffic is being dropped by fxp0 or not - tcpdump 
says that a request was made, after all, so should I assume this was 
sent over the wire as well?  ed0 certainly never gave that impression.

	So this is where I'm stuck.  Any help is greatly appreciated.  If my 
question doesn't have an easy answer, would someone mind pointing me in 
the right direction?

Thank-you,
-David