When eth0 is set to static IP or DHCP then eth0:avahi looses it's local connections

[Nils Kassube]

Georgios Kolomvos wrote:
> My ubuntu 7.10 pc connects to the Internet through a USB ADSL modem
> (ppp0). I want to share this Internet connection with a windows vista
> pc that connects to my ubuntu pc with a crossover ethernet cable. This
> local connection seems to work fine since both PCs see each other. The
> ethernet interface used by the ubuntu pc for the local connection is
> eth:avahi and it works fine as long as the setting of eth0 is "enable
> roaming mode" (it is not possible to set any settings on eth:avahi from
> Network Tools because "the interface does not exist..."). But in this
> case (when eth0 is set to "enable roaming mode"), eth0 does not have
> any IP address (Network manager shows that it has 0.0.0.0 as IP
> address). So when i try to start a firewall through Firestarter (so
> that i could "Enable Internet connection sharing"), the firewall cannot
> start because "The device eth0 is not ready" (it is logical since it's
> IP address is 0.0.0.0).
>
> When i try to set eth0 to static IP or DHCP, then the firewall Starts
> nicely but interface eth0:avahi looses its IP address and the local
> connection with the windows pc is lost. It seems that eth0:avahi
> interface works properly only when the setting for eth0 is "enable
> roaming mode" (in this case there isn't any entry for eth0 in
> /etc/network/interfaces file).

Your problem seems to be that eth0:avahi is a virtual interface especially 
made for roaming mode, but it uses the physical interface eth0. I think, 
roaming mode is not necessarily useful in your situation - better use 
eth0 with a static setup. That would be about this procedure (I haven't 
tested it):

- Unselect roaming mode.
- Use the network tools to give your eth0 an IP address 192.168.2.3 and a
  network mask 255.255.255.0.
- Setup your Linux machine for "connection sharing" with firestarter, as
  you intended to do.
- Setup your Windows machine to use a static IP address 192.168.2.4,
  network mask 255.255.255.0 and gateway your Linux machine (192.168.2.3).

Please note: I made the assumption that you know how to use the network 
tools and firestarter which you mentioned. If you need more help with it, 
please let us know.


Nils