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currently running Ubuntu 11.10. my wireless connection to our router has already been established but when i open Firefox, the page says server not found.please help me

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It's disappointing that so many people forget that pinging still requires a name lookup. When your testing connectivity you should always try both an IP address and a dns name when pinging. This will tell you straight away if you have a DNS problem. Details are in my answer below. – Jeff Welling Apr 5 '12 at 14:59

I would suggest resetting your Router and your Modem (if you haven't done so already). In case you haven't I would suggest powering down your modem, router, and PC. Wait 30 seconds and power up your modem...wait 45 seconds to 1 minute and power up router...wait 45 seconds to 1 minute and then power up your PC.

I think this should fix it by resetting the IP connection. I know this works all the time with Windows.

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LOL...please explain the negative vote please...basic troubleshooting 101?? – daslinkard Apr 5 '12 at 19:44

Try this, go to terminal and try ping I know you've tried pinging and that it fails, but the difference between pinging and (both are Google) is that doesn't require a name lookup in order to test connectivity.

If the ping to is successful, then you have a DNS problem, and should try changing your DNS settings to use Google's DNS servers (,

If the ping fails, then you have no internet connection at all, and need to either configure the router or modem properly. Your best bet for configuring the modem would probably be to contact your ISP. Most routers are plug-n-play so that shouldn't need configuring, but if it does we can help you with that as well.

If you know how, try logging in to the router to check the status of the internet connection on the router. It's possible, though unlikely, that the internet is getting to the router but no further.

Edit: Also, though this probably goes without saying, check that you have the modem plugged into the correct port on the back of your router. There are usually 4 or more regular ports, and one 'uplink' port where the modem plugs in. If you plug it in to the wrong port, you will likely have network trouble.

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Thanks for this. I can ping but not How should I go about changing my DNS settings the way you recommend? – cboettig Jul 14 '12 at 15:11
Ah, never mind, seems these instructions worked: Thanks for a great answer. – cboettig Jul 14 '12 at 15:20

try the following command in terminal


If it reply then your internet connection is ok, problem is in firefox. Maybe firefox is using proxy, to disable it Go to Edit>Preference>Advance>Network. select Settings for network and check no proxy.

If you can not ping that means something is wrong in routing. Check your router that is it provide service for specific(mac address filtering) machine? make sure your device mac address is in router

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i tried ping ping: unknown host – Jeff Dela Cruz Apr 5 '12 at 5:23
Right-click on network icon (gnome-panel) and select connection information. Take a screenshoot(alt+prnScr) and post the image. – shantanu Apr 5 '12 at 5:50
that was the image @shantanu – Jeff Dela Cruz Apr 5 '12 at 9:24
Don't forget, failure to ping a DNS name could also be indicative of DNS problems, it isn't always an automatic indication of IP connectivity problems. – Jeff Welling Apr 5 '12 at 15:04

Try in terminal

2.if its work then do ifconfig and see which eth0 or eth1 or so.... connected

3.then do it ifup eth1 or eth2 or any other which is connected in the system.

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i tried ping ping: unknown host – Jeff Dela Cruz Apr 5 '12 at 9:37
your net connection good ? – Raja Aug 29 '12 at 20:00

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