Internet sharing over multiple interfaces

[lutz <lutz reinhardt tu-bs de>]

Hi,

the power adapter of my router broke and atm I am using NetworkManager
to create a Internet connection and share it with other PCs. The network
setup is, that all devices (including the ADSL-modem) are connected to
an Ethernet switch.

The computer, which is managing the Internet connection got two wired
network interfaces eth0 and eth1. eth1 is used to create the ppp0
connection and was at the beginning the only card, which is connected to
the switch. I activated "Shared to other computers" in the IPv4-tab of
both cards, but only with eth1 this seems to work. So i had to use
another Ethernet cable for connecting eth1 with the switch, too.
Initially I wanted to use eth0 for my notebook.

I am using Debian Sid AMD64 together with NetworkManager 0.8 and
dnsmasq-base at version 2.52.

Here is what ifconfig tells me about the interfaces eth0 and eth1:
$ ifconfig 
eth0      Link encap:Ethernet  Hardware Adresse 00:22:15:81:5a:c5  
          inet Adresse:10.42.43.1  Bcast:10.42.43.255
Maske:255.255.255.0
          inet6-Adresse: fe80::222:15ff:fe81:5ac5/64
Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
          RX packets:49966 errors:0 dropped:134 overruns:0 frame:0
          TX packets:61232 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000 
          RX bytes:5844382 (5.5 MiB)  TX bytes:74125324 (70.6 MiB)
          Interrupt:17 

eth1      Link encap:Ethernet  Hardware Adresse 00:22:15:81:78:1a  
          inet6-Adresse: fe80::222:15ff:fe81:781a/64
Gültigkeitsbereich:Verbindung
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metrik:1
          RX packets:205201 errors:0 dropped:0 overruns:0 frame:0
          TX packets:92754 errors:0 dropped:0 overruns:0 carrier:0
          Kollisionen:0 Sendewarteschlangenlänge:1000 
          RX bytes:239220870 (228.1 MiB)  TX bytes:11124327 (10.6 MiB)
          Interrupt:18

This is dnsmasq:
$ ps aux | grep -i dnsmasq
nobody    2231  0.0  0.0  21168  1192 ?        S    09:31
0:00 /usr/sbin/dnsmasq --no-hosts --keep-in-foreground --bind-interfaces
--except-interface=lo --clear-on-reload --strict-order
--listen-address=10.42.43.1 --dhcp-range=10.42.43.10,10.42.43.100,60m
--dhcp-option=option:router,10.42.43.1 --dhcp-lease-max=50
--pid-file=/var/run/nm-dnsmasq-eth0.pid

Is there a way to get this working with NetworkManager? At first I was
pleased that NetworkManager can handle sharing one connection, but now I
don't know how I could solve this without setting up a router myself.

greetings Lutz