Doug Gough wrote:
>
> I'm not able to get my LM8.0 box to work as a router between to LANs.
>
> When it boots, I get a message saying IP forwarding is on.
>
> My routing table is very simple, using static routing as follows
>
> 131.103.1.0 131.103.1.10 255.255.255.0 UG 0 0 0 eth1
> 10.10.0.0 10.10.90.99 255.255.0.0 UG 0 0 0 eth0
> 127.0.0.0 * 255.0.0.0 U 0 0 0 lo
>
> It couldn't get much simpler. I have checked and rechecked the IP addresses and
>netmasks, and found everything to be correct.
>
> >From the 131.103.1.0 network, I can ping 131.103.1.10 and 10.10.90.99, but I can't
>reach anything else on the 10.10.0.0 network.
>From your "cont'd" followup post:
> Sorry, I forgot to say that I can ping the 10.10.0.0 network from the router.
So... you can't *and* can. :>
OK... here's the deal... you are pointing packets destined to 10.10.x.x at
10.10.90.99 *BUT* that router CAN'T route them if it has the same netmask 'cuz
it would have to route them back out to the same segment...
NetA---10.10.90.99---+---[eth0[LM8.0]eth1]---+---131.103.1.10---NetB
| |
10.10.0.0 131.103.1.0
Instead, remove the GW entries which will allow the LM8.0 box to ARP request
directly to the hosts (which are local) rather and *trying* to hop in/out of
10.10.90.99 or 131.103.1.10.
Assuming the routers are there to access Net[AB], you can turn on proxy ARP as
Nathan suggested in his reply to simplify other host configuration requirements
and reduce unnecessary router hops and resultant ICMP redirects.
Proxy ARP -- a short course: when a host ARPs for a remote destination without
trying to go thru a GW, a router which knows how to get to that destination will
Proxy ARP reply allowing the host to send its packets to what it thinks is the
destination (hence "proxy"). Note that a Proxy ARP reply is no guarantee of the
best route, just a viable route; but in your case, unless the topology is more
complex, only the best router will reply since the other router would have to
route packets back out the same interface they come in on... not what routers
are 'trained' to do...
BTW, you have no default route... so the LM8.0 machine will not pass traffic
between NetA and NetB...
HTH,
Pierre
> I've read as much as I can find on the subject, undoubtebly missing the most simple
>and obvious :-)
>
> Any hints and help would be appreciated.
>
> Thank You
> Doug Gough
> Computer Services
> Pacific Academy
