[lug] routing

[charles at lunarmedia.net]

I'm not quite following what you mean by the 192.168 address is unable to
match on that network. Linux should be able to add a route with any subnet
mask all the way through /32 for routing purposes. If the local lan is
192.168.0/24 with a static route for 172.16/16 and a gateway of
192.168.0.4, I don't see what additional configuration would be required
for the packet to exit the network correctly towards 172.16/16.

I think however that the problem he may run into is for the return path of
the packet. Even though you he may have his local lan configured
correctly, to have packets destined for 172.16/16 to be sent to
192.168.0.4, all the machines on the 172.16/16 network, will need to be
configured such that in order to reach 192.168.0/24, they will need to
have a route set to hit the 172.16/16 of his dual interface machine.

If you could elaborate on how the netmask would prevent this routing from
occurring, I'd appreciate it.



On Fri, 12 Jan 2001, Michael J. Pedersen wrote:

> On Fri, Jan 12, 2001 at 01:34:53PM -0500, Hugh Brown wrote:
> > My problem is I'm not sure what I set as the static route.  I tried to
> > do
> >
> > route add -net 172.16.0.0 gw 192.168.0.4
> >
> > and it told me that it wasn't feasible.  My thought was that I want all
> > traffic destined for the net 172.16.0.0/24 to use 192.168.0.4 as the
> > router.  So what static route can I add (I do only have 3 workstations
> > so that will be easiest until I get more savvy about network things).
>
> There's a mild trick to this that's easy to miss. 172.16.0.0 has a netmask of
> 255.255.0.0 (most likely). 192.168.0.4 cannot match that netmask, as such it
> can't be found on the 172.16 network. As such, it can NOT be a gateway for
> what you are trying to do. However, it is possible to do so. I'm gonna need a
> few minutes to describe everything, so wanted to give you a short heads up.
> I'll be sending another email in a minute.
>
>