Subject: Routing problems

From: Jukka Marin <[email-masked]>

Dear All,

I am trying to set my BSD box as a gateway between my local Etnernet
network and a SLIP interface.  I recompiled the kernel with -DGATEWAY
and started routed.

The BSD box can access the local net (via ether) and world (via SLIP)
without problems.  Also, world and local net can get to BSD.  However,
when I try to ping world from the local net, the packets are not
routed to the SLIP interface.  Instead, netstat -p ip lists them as
"packets not forwardable".  The same happens when the world tries to
ping my local net (the machines in the local net, actually).

What am I doing wrong?

  Jukka Marin

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From: David Jones <[email-masked]>

> network and a SLIP interface.  I recompiled the kernel with -DGATEWAY

You may also need IPFORWARDING defined.

> ping my local net (the machines in the local net, actually).

A few other things to try:

Traceroute from one side of the gate to the other.  What ICMP messages
od you get?

Use netstat -r to examine the routing tables.

Routed uses RIP to "auto-load" the routing tables.  For this to work, your
internet provider must agree to run RIP over the SLIP interface.  In
addition, you may have to insert static routes for your local net.  There
may be other things you need to do in order to "advertise" your network
to the outside.  Your IP provider should be doing this for you, so that
the world's routers know of you even if the SLIP link is not active.

The Toronto Free-Net is running NetBSD 0.9/i386 as a firewall gateway,
and packets get routed fine across two Ethernet interfaces.  (A kernel
hack filters packets being forwarded across the bridge.)

-- 
David Jones, M.A.Sc student, Electronics Group (VLSI), University of Toronto
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From: John Shardlow <[email-masked]>

Hi Jukka,

> What am I doing wrong?

Please post the output from netstat -r

(I haven't tried this with NetBSD but I have set up a similar thing using
 SunOS).

John
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