Recently, I had reason to turn off my ADSL modem - a Thompson SpeedTouch585i - yes, its wireless.
Since then, I have had nothing but troubles trying to connect my laptop back to the internet via this particular modem. (Edit: I havent got a spare modem )
I am running edgy on a pentium III laptop, using a D-Link wireless card. (Edit: I think its worth pointing out here that it doesnt matter if I go wireless, or via ethernet, I get the same result)
The network connection is good, as I can browse the modem's user interface, and establish telnet sessions to the modem, I can ping the modem, and also anything else connected to the network, but cant ping my WAN IP address, the WAN IP address's gateway, or even good ole' 66.249.89.99 (google.com.au ip address)
I know it isnt the internet service itself, as it shows up in the radius logs, and shows as being connected at the ISP's end, Plus, my main PC (where I am typing this from) is able to get connected wirelessly through the same modem on both Ubuntu and Windows.

I had a thought that it may have had something ot do with iptables, so, I flushed them all, not that there was anything there anyway, and I also uninstalled the firewall I had installed on the box.
None of this seems to have brought about any connectivity back to my laptop.

I have had this problem once before, and because there was practically nothing on the laptop, I just reinstalled Ubuntu, however, this time around, this option is an option of last resort, as I have a few important files and emails on there that need keeping!

One more thing before I leave you guys alone......I mentioned that when I try to ping the WAN IP address, I get nothing. When i try to traceroute to 66.249.89.99, the trace dies just after the WAN IP. Could this be somthing to do with the way the packets are being sent?
I swear to god I have not touched anything in the way of networking for over 6 months now.

Can anyone suggest anything that may either get me going again, OR at least point me in the right direction?

If you require any information from the laptop, please let me know and I can get it for you.

Thanx

Already tried to kill & run dhclient (or dhcpcd, depending on which one you have installed) manually for your ethernet device (eth0 or eth1) to fetch new addresses via dhcp? Or tried to setup your network to loopback only (remove all other network configurations), then re-setup your "real" network?

There are also interface configuration files for your interfaces (eth0 and/or eth1), and for some reason or other they may get unneeded lines into them (basically there needs to be two or three only, you can check some websites which they are in addition to the lo device); I had to "clean" them once to get my network work again. Actually the network tool that I had jammed shouldn't use those files at all, but apparently it did do something with them since the cleaning helped.

I suppose one thing I could try is to allow the modem to assign a new IP address to the laptop when it connects.
Currently, I have MAC address filtering on the wireless card, and when it connects, it gets assigned the same IP address. I dont have the same on the eth card though, which is wierd.

When you mention eth0 config files, I would assume that you are talking about the file /etc/network/interfaces
I guess I will check this file to see if there is anything in there that is causing my problem.

Marking this as resolved.

Turns out that my laptop, for some strange reason it had dropped all knowledge of the default gateway (LAN side of the modem)
I added the routes back in, and viola! I have access again.

Huzzah!