One more thins is. At /etc/defaults/avahi-daemon there`s string AVAHI_DAEMON_DETECT_LOCAL=1, try '=0' and dont forget move /etc/rc5.d/avahi-daemon avay.
In Administrator -> NetworkTools close to Network device field should be only lo and eth0 devise, without eth0:avahi or or smth else.

Note: Once installed Ubuntu 8.04 Hardy, network and internet is good and work right after installation. Without any tuning ! )

If you look up what avahi does, you will see that it is a service for configuring local networks and assigning ip addresses in the absence of a dhcp server, and can also broadcast the availability of certain services such as available printers on those networks. On the default hardy installation, if a configured ethernet port does not receive an ip address from a dhcp server within a timeout period, then the avahi daemon assigns a "link-local" address to the port. These addresses are always in the 169.254.x.x range. This is for instance, how you can connect 2 computers together with a crossover ethernet cable, or plug a network printer and computer into a switch or hub, and have the computer find the printer even though no dhcp server is running to assign addresses. Normally avahi and the related services are configured to do nothing if an address is assigned by dhcp or statically. I'm oversimplifying avahi and related services here, but usually avahi and the related mdns service do not interfere with normal network operations. I think this focus on avahi is just diverting you from finding the real problem (Of course I could be wrong!) The avahi address is created BECAUSE you are not getting an address from DHCP. It is NOT the CAUSE of the dhcp failure, but a consequence of it.

Yes, connecting my laptop to the ethernet (so it's recognised as eth0) rather than the USB (recognised as eth0) causes exactly the same ipconfig result, except the avahi IP address is assigned to eth0 instead of eth2.

I kinda guessed this from what you said before and googling avahi. So as far as I understand it, my modem isn't assigning my laptop an IP address which means it can't find a connection; possibly because it's not configured for multiple IP addresses/users?

Thanks
Hugh

That is a possibility. The DSL and cable modems in current common use in the USA can certainly be configured that way, though it would be unusual for an ISP to do so. However it is not so unusual for an end user to configure them to limit the number of ip addresses handed out, or to only assign an address to hosts with specific ethernet addresses, as an extra security measure. I don't know what common practice in the UK is. Have you taken a good hard look at the network settings on the windows machine? You might want to google "pppoe" and see if it applies to you, though your ISP should be better able to help.

Also, can you access the setup of your modem from the Windows machine? and have you ever tried the laptop on another ethernet network? And also, if you have a firewall running on the laptop, temporarily disable it while debugging this problem!

Sure, i khow that. DHCP server can not take me an IP when i try ifup eth0.
But my Network Manager configured to get IP via DHCP. It works !) Though the avahi-daemon doesn`t take any action. This is an issue i`m thinking of.

I can access the setup of the modem in windows off my PC. I haven't got a windows OS installed on my laptop - the original OS corrupted which is one of the reasons for installing Ubuntu.

I haven't got another ethernet network to connect to at this time, although I see the relevance, if I could connect to another internet without trouble then it would be my network that is causing the problem. I'll see what I can do about finding another ethernet to connect too.

I haven't set up a firewall in ubuntu, so I kind of assumed one wasn't running. Another thing I'll look into.

Thanks for the ideas.
Hugh