Weird loss of Linux access to Google/Yahoo/Wikipedia... DNS? IPV6? But Win XP works.
 

Doing new Linux Mint 9 installations for a friend we found that neither of them would access Google.com, or .co.uk - ditto Yahoo and Wikipedia. All came back with 'not found'.

His crusty old Dell laptop with Win XP SP2 & Firefox was fine.
Other sites, eg LinuxMint, Ubuntu, LQ, were all good in Linux.

Tried my own laptops and netbook etc running Ubuntu 9.04/9.10/10.04 had the problem too. Tried varii browsers in Linux - Firefox, Epiphany, Mid, all the same.

Used 'ping google.com' and got a roughly 45 ms response, similar numbers on google.co.uk, yahoo.com, etc.

Then put the numerical addresses in the ping results into the Firefox address bar - success! Up comes the Google (or Yahoo etc) page. But as soon as you search with it is back to 'not found'.

Reminds me of the funnies with IPv6 a few years ago - but disabling IPv6 in Firefox 'about:config' did not help.

Being a complete idiot I have mislaid the notes detailing the ISP and ADSL modem used, and cannot remember them .... will repost when I have the info, since am now travelling.

Help, please! All suggestions welcome!

Thanks in advance, Ben

It's DNS issue if the IP works and the hostname does not.

cat /etc/resolv.conf

You described the symptoms but gave no real useful info regarding config.

Then his ISP's DNS seems to be OK

Then linux's DNS seems to be OK.

Then it is probably not a "mint thing", though mint is ubuntu-based.

Then it's unlikely to be a browser setting.

Again, it looks like DNS is working if ping works OK on all sites, even if http does not.

All very strange.

Are your linux machines running any firewall software ( sudo iptables -L ) ?

Does his router have a mis-behaving firewall?

But this would not explain why win is OK. Unless: - is win connected by cable, and everything else connected wirelessly? If so, try connecting linux with the cable. Then see if special iptables rules are being applied to the wireless interface by the router.

Disabling IPV6 with the more modern 'buntus is by passing the parameter ipv6.disable=1 to the kernel at boot time.

Mysteriouly vanished...?
 

Thanks to Tredegar and Timetraveller for your kind and helpful responses! For completeness - we had no firewall enabled on the machines at the time, relying on the router box which was showing good results - 'Shields Up' had reported it as effective.

Must apologise for my tardy return.....
Been on the road (returning home) for some time, to find that the BT line was down - no 'phone and no b/band! Fixed now, thank goodness!

Well, I called my friend to discuss the problem in the light of your suggestions, to be told that a couple of days later, it had disappeared.

It must have been a service issue, I guess - because all the varied Linux machines showed similar symptoms and the two still there now do not. My friend has certainly not modified anything - not even an update, yet.

Other than this obscure issue, I can report that Mint 9 seems very solid, and has survived the intervening time in the hands of a happy newcomer to the world of Linux. He is due to visit me soon for a bit of hands-on training, which should be fun. Talk about the blind leading the blind! <grin>

Thanks and best wishes to you both. I will now attempt to set this thread as SOLVED.

All the best, Ben

PS - fyi- no wireless was used, everything was on cabled Ethernet

I see things like this occasionally, and it's my ADSL router at fault. The router gets a public IP when it connects to my ISP, and is the default gateway.
It got so bad I now power cycle it off at 01:00 each day - problem gone. Will get around to replacing it sometime.

That's interesting!
 

Thanks for that, syg00.

Not sure if that was the problem - since we power-cycled everything a couple of times whilst wrestling with it - but it could indeed have been a cranky router. I quite like *some* routers.

*/Off Topic/*

Some years ago I was just fooling around with a then-new Actiontec router and it became a major moment for me - idly tried to Telnet into it from SuSE 10, and got a login - my usual router login and password worked fine.

Found myself looking at a # prompt - seems I was logged in as root on this thing about the size of a generous cigarette packet. Up until that moment I had been stuck in mindset that said:
...................GNU/Linux = UNIX = mainframe-or-hefty-desktop

Since then I have had a lot of fun trying (and sometimes succeeding) in prising open small/old systems and installing Linux. Had most success with antique battle-hardened iTronix laptops using Puppy Linux or Slitaz.

All the best, Ben