Re: questions about routing via tun(4) interfaces

[Chuck Musser <cmusser%sonic.net@localhost>]

> The 4.4BSD routing socket code has a number of options like -interface
> and -link, and I am not sure they are 100% as intended; certainly they
> are complicated and totally understood by very few.
> 
Complicated, indeed. This particular use case, in which the tun interface
is used to route to a remote network, does work. Another variant, using the
tunnel to route to a specific host on the remote end, I haven't gotten to work.
In this scenario, a proxy ARP entry exists so that the router will receive the traffic
on behalf of that remote host, Proxy ARP seems to function correctly, but
forwarding does not: packets bound for the remote host arrive on the local
network interface, but don't get forwarded onto the tunnel. It looks like a
routing problem, but I can't confirm the packets are being explicitly dropped
or something weird is happening. IP forwarding has been enabled.