dns server problem

suahilahmad4207 · 2013-02-07T10:57:41.000Z

dear friends

i have a network of about 80 systems and from yesterday in some systems (40 to 50 )systems its shownimg no internet connection but i am able to acess theinternet from them its looking like as a dns problem

can any 1 sugesst me how to make it right

optimaximal · 2013-02-07T11:01:51.000Z

Are these Windows 7 machines?

suahilahmad4207 · 2013-02-07T11:35:29.000Z

yes

optimaximal · 2013-02-07T11:42:15.000Z

Windows 7’s network subsystem (presumably) checks for internet connectivity by trace/pinging an external site - likely one of Microsoft’s domains.

If it can’t get past a firewall or other part of your network, it throws an error, even if said firewall is letting all other traffic through.

Someone else might be able to confirm exactly how it works, but it’s almost certainly a firewall issue. Can you check the proxy/firewall logs for the machine/user accounts on the problem machines to see if any explicit connection attempts are being blocked?

byronviljoen3150 · 2013-02-07T11:51:22.000Z

Are you running a DHCP server? - and if so are they retrieving the correct settings as specified in the scope?

markreid8463 · 2013-02-07T12:04:45.000Z

I had a strange one the other day, Firewall correct, DHCP Correct, I disabled IPv6 on the PC and it worked. This might be handy if what the chaps said above doesn’t help.

suahilahmad4207 · 2013-02-07T12:08:51.000Z

yes we are running dhcp server .@byron

@andrew i checked windows firewall thats ok can it be happen bcoz of the main router firewall

and i am able to acess internet but the problem is only that its showing no internet connection icon

suahilahmad4207 · 2013-02-07T12:11:05.000Z

ireidy thnx for cmnt but i checked that before but that also doesnt worked in my favour

byronviljoen3150 · 2013-02-07T12:15:23.000Z

OK, are you sure you have tried the obvious?

ipconfig /release
ipconfig /renew
ipconfig /flushdns
Possibly a reboot of one of the PC’s giving issues?

By the way… do any of these PC’s share anything in common? a switch or access point perhaps?

I also know that some Anti-Viruses can cause similar issues (Something to do with link checking)

vishalbaisane0638 · 2013-02-07T12:23:40.000Z

please make DNS server IP 8.8.8.8

suahilahmad4207 · 2013-02-07T12:40:05.000Z

some of them have common but not to all

vishalbaisane0638 · 2013-02-07T13:26:54.000Z

check the proxy setting in internet option. Set no proxy in internet option.

suahilahmad4207 · 2013-02-07T13:53:38.000Z

no bro internet is working but the thing is icon and this prob is on abt 50 systems

normhare6537 · 2013-02-07T20:48:50.000Z

Configure one of the PCs with static addresses and see if it solves the problem. Might also try restarting your DNS server.

markreid8463 · 2013-02-08T10:02:46.000Z

do they have Kaspersky installed?