Possible DNS problem?

[Tricky_Dicky]

I'm not sure what's going on here, so any help or suggestions would be greatly appreciated.

 

Reasonable size network (50 PCs and 120 laptops, 2 DCs with DNS, DHCP) and every now and then the laptops won't log on to the network because it says it can't find the domain controller. By logging on to the local machine you can then just re attach to the domain and it's happy.

The DNS thats being given out is for the local server and also 2 of the LA one's as second and third. It was set-up this way by the LA approved supplier, should it have been?

 

Any ideas why it's doing this?

 

Cheers

Rich

[jcs808]

Not sure what's going on but config your DHCP to give out the IP of the local DNS, and then config the IPs of the LA DNS as forwarders in your local DNS.

[Cools]

Don't Give out the LA ones on your network.. only the one's to your local DNS server..

 

then in you DNS server config the LA DNS as a forwarder's

 

Jobs a good one.

Edited February 10, 2010 by Cools

[Tricky_Dicky]

Thanks for the quick replies.

Just before I do this can I just check a couple of things. I have 2 servers, both have DNS enabled, should I put there IP addresses into the DHCP DNS Server Scope (option 6) and remove the other two DNS servers that are currently in there that belong to the LA?

The forwarders appear to have already been setup to the External DNS servers on both machines.

Would screen dumps help explain what I mean?

Rich

[pete]

Thanks for the quick replies.

Just before I do this can I just check a couple of things. I have 2 servers, both have DNS enabled, should I put there IP addresses into the DHCP DNS Server Scope (option 6) and remove the other two DNS servers that are currently in there that belong to the LA?

 

Yes

 

Also, check that the two internal DNS servers only have themselves in their DNS settings (127.0.0.1)

[Michael]

Reasonable size network (50 PCs and 120 laptops, 2 DCs with DNS, DHCP) and every now and then the laptops won't log on to the network because it says it can't find the domain controller.

 

If it was a DNS problem it would affect more than just the laptops, but workstations too. Your problem undoubtedly is wireless authentication and/or DHCP related and not DNS related.

 

If you can find a laptop which cannot find the domain, logon to it locally and have a look at the wireless settings and whether the machine has an IP and whether you can ping your DC.

[Cools]

The other thing to look at Wifi wise on the laptops ..

Only use MS wifi Client, not a 3rd party one like Intel Pro Wi client..

also un join it from the domain and rejoin it over the wifi..

some times in you do it on the Wired NIC it look there 1st for the domin .

and take 5 min to swap over to Wifi..

 

and a good set up on the DNS will save problems.

 

all client's DNS and server's DNS should look for the Local DNS servers only, it's like asking a friend for direction to loo in your house that has never been to.

[srochford]

If it was a DNS problem it would affect more than just the laptops, but workstations too. Your problem undoubtedly is wireless authentication and/or DHCP related and not DNS related.

 

It might be a wireless problem but he has far more laptops than desktops so he's going to see intermittent problems like this more frequently on laptops than desktops.

 

The DNS settings are wrong so it does make sense to fix them; even if this turns out to be an issue with the wireless network, it does no harm to fix things which you know are wrong.

[Tricky_Dicky]

it's like asking a friend for direction to loo in your house that has never been to.

 

That's a great analogy.

 

I first thought the problem would be a wireless one, but I can't see how it could be. We use a Ruckus system and all the clients have had the 3rd party software removed so it only uses the Windows one. The only wireless that is in there is the Ruckus one and the children/teachers have no access to change anything like that.

 

Could there be some external factor changing the wireless settings or blocking the authentication?

 

As srochford said it happens a lot more on the laptops and I hadn't had a reported case on the desktops until this morning when I tried to log on I got the "domain could not be contacted". I'm presuming that the way DNS servers work, like most servers, is that they try and give out the correct information but if that server is to busy at the time then the next DNS server in the entry will try and process the request. Hence why when a class of 30 laptops log on the server can only handle so much and the incorrect DNS was being used.

 

Rich

Edited February 10, 2010 by Tricky_Dicky