Subject: Re: SLIP packet routing problems (fwd)
To: None <netbsd-help@NetBSD.ORG>
From: Gerrit Graf <gerrit@toucan.toppoint.de>
List: netbsd-help
Date: 03/17/1995 10:35:04
Hi,

> From the NetBSD box I can do everything. I have full access to the 
> Internet, and no problems reaching any host. The default route is set 
> to my router, and the standard routes for the interfaces are in place. 
> (I'm not currently on the system; I haven't got news and mail working 
> yet 8^( or I'd send actual netstat -nr output...)
> 
> The NetBSD box is a primary nameserver, and resolves addresses perfectly
> for the system SL/IP'd in, but that system can't see beyond the SL/IP
> interface (or so it seems). 
> 
> For example, from the SL/IP'd system (I'll say remote host) I can ping 
> 204.191.16.2 (my NetBSD Box), 204.191.16.9 (the NetBSD end of the SL/IP), 
> but that's about it. I can't ping the router at 204.191.16.1 or the bridge
> at 204.191.16.253. The netmasks are all set for 255.255.255.0...

Looks like the routes back to the SL/IP'd are not set so the ping packet
actually reaches it's destination but this one does not know that this packet
should be returned via a gateway.

What you should do is add a proxy arp entry (look into the manpages for arp)
so that the NetBSD BOX (I understand that this is the one which shares a lan
with the bridge) answers arp requests for your dial-in-system with it's own
Ethernet adress.
The result is that the IP-Adress 204.191.16.9 is resolved by arp as the NetBSD
Box so that it gets anything destined to 204.191.16.9. Since it's routing
tables should know that 204.191.16.9 ist attached via slip, it'll forward the
packet.

This works great for me.

BTW: You should add the arp entry on dial-in and delete them when the connection
     is terminated. Look into the sliplogin-manpages.

Have fun

  Gerrit
-- 
Gerrit Graf                                         gerrit@toucan.toppoint.de 
Holtenauer Strasse 42                             gerrit@bwl.uni-kiel.d400.de
24105 Kiel                                                CIS ID# 100121,1416
Germany                                           Tel.: (voice)+49 431 578428 
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