DNS stopped working

[kglidh]

I'm using ndiswrapper on FC7 2.6.23.1-10.fc7 and wasn't having any problems at home or in a class I was in last week. But now I'm at work and although I can get an IP and get the resolv.conf, I can't get DNS to work. I can't ping the DNS servers or anything. I'm sure there's some file that has an old config or a lock or something but I'm not sure where to look. I tried to use my Sprint card and I get an IP with that, as well. But I run into the same problem with DNS. Does anyone have a suggestion on where I could/should look first?

[Zotter]

Key will be to verify you've a working connection before you can go troubleshooting services.

what is your default gateway router? As root - run 'route'
Should be a line that starts with 'default' - take that IP and ping it.

If you can't ping your default gateway IP, then chances are your WiFi isn't really connected - even if it's displaying an IP address. Could well it's cached and not being assigned.

Once you know you can ping your gateway, try:

nslookup - <ip of your dns server> <enter>
Make sure you get that 'dash' in there. I know, I know - 'dig' is the new way - you can read it's man page to do the same thing there. That'll force nslookup to do lookups against the server specified - ignoring settings in your /etc/resolv.conf. You may want to try one of the OpenDNS servers as well - see if you can differentiate between your system not being able to do DNS lookups or a problem with talking to your particular DNS server.

That should give you some clues as to where the problem lies.

G'luck!

[kglidh]

Thank you for responding. I did check the route and it did reference the router for the network I was trying to access as the default. And I wasn't able to ping it. The Sprint card creates a ppp0 (as opposed to wlan0) and I wasn't able to ping that router either. Since then, I've gone home and my computer was able to connect to my home network just fine. I'm able to create a VPN connection (tun0) without any issues to work. I noticed that there is another kernel and ndiswrapper update so I'm applying those and I'll test my Sprint connection when I reboot.

[kglidh]

I'm back at work after my wlan0 worked fine at home and I'm in the same situation with the wireless here. I get an IP. The netmask and DHCP server are correct. I can stop and start the wireless and it gets the IP (which is different from last time but in the same area). I even get the correct DNS servers written to the /etc/resolv.conf. But I can't nslookup or ping anything outside of my machine. I assume its a routing issue but I don't know what else to check. I ran the route and the default is the IP of the gateway (validating with a Windows box that works).