Re: [LARTC] Linking two networks - =?unknown-8bit?q?Roch=C3=A9?= Compaan

From: =?unknown-8bit?q?Roch=C3=A9?= Compaan <roche@upfrontsystems.co.za>
To: lartc@vger.kernel.org
Subject: Re: [LARTC] Linking two networks
Date: Sun, 01 Dec 2002 07:06:47 +0000	[thread overview]
Message-ID: <marc-lartc-103872659518427@msgid-missing> (raw)
In-Reply-To: <marc-lartc-103865308106021@msgid-missing>

Hi Abraham

> Ok, so this (otoh so don't blame me if it doesn't work *g*) in your inittab
> should do the job:
> 
> ------------< snip <------< snip <------< snip <------------
> # At office
> S0:23:respawn:/usr/sbin/pppd /dev/ttyS0 115200 modem noauth crtscts persist \
> 192.168.1.10:192.168.2.10 nodetach >>/var/log/leased.log

Instead of re-assigning 192.168.1.10 to eth1 at
the office I just set loc_ip:rem_ip in my ppp options to
192.168.1.1:192.168.2.1 because to many hosts already point to
192.168.1.1 as their gateway. I think this boils down to the same thing.

This works partially. I have one host behind 192.168.2.1 (gateway at
home) with the ip 192.168.2.2. I had to add a route to 192.168.1.1
(gateway at the office) before 192.168.2.2 could see 192.168.1.1:

    route add -net 192.168.2.0 netmask 255.255.255.0 gw 192.168.1.1

So now 192.168.2.2 can see 192.168.1.1 as gateway, but the hosts on the
192.168.1.0 network at the office can't reach the 192.168.2.0 network at
home.

I tried to ping 192.168.2.1 from 192.168.1.2 (a host behind the
192.168.1.1 gateway) and got no response so I investigated with tcpdump.

On 192.168.1.1 the output of tcpdump -i eth1 is:

10:20:43.432529 < 192.168.1.2 > 192.168.2.1: icmp: echo request (DF)
10:20:44.432621 < 192.168.1.2 > 192.168.2.1: icmp: echo request (DF)
10:20:45.432556 < 192.168.1.2 > 192.168.2.1: icmp: echo request (DF)
10:20:46.432560 < 192.168.1.2 > 192.168.2.1: icmp: echo request (DF)

So no "echo reply", then I did a tcpdump -i ppp0 to see if these packets
actually reach the ppp device and they don't.

This is how the routing table at the office looks like now:

Destination Gateway      Genmask         Flags Metric Ref Use Iface
192.168.1.1 0.0.0.0      255.255.255.255 UH    0      0     0 eth1
192.168.2.1 0.0.0.0      255.255.255.255 UH    0      0     0 ppp0
196.x.y.51  0.0.0.0      255.255.255.255 UH    0      0     0 eth0
196.x.y.48  0.0.0.0      255.255.255.240 U     0      0     0 eth0
192.168.2.0 192.168.1.1  255.255.255.0   UG    0      0     0 ppp0
192.168.1.0 0.0.0.0      255.255.255.0   U     0      0     0 eth1
127.0.0.0   0.0.0.0      255.0.0.0       U     0      0     0 lo
0.0.0.0     196.44.35.49 0.0.0.0         UG    0      0     0 eth0

-- 
Roché Compaan
Upfront Systems                 http://www.upfrontsystems.co.za
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