Active Directory Stops Responding

[adrianm83]

We have set up Active Directory on a new school's

server, which is running Windows Server 2003. The primary purpose of

this is to allow a group policy to be applied to 20 laptops.

 

The server is also be providing server-side storage for the accounts

The server is connected to a network switch, which in turn is

connected to a wireless access point. The server is also used by Censornet proxy server

which, when authenticated by Active Directory, is used by clients

to access the internet. In the IT facilities there are 20

laptops which connect to the wireless access point, each of which is

configured to access Active Directory on the server.

 

The problem is that when the laptops log into the server, it works for

a short time then the laptops become unresponsive.

At first we thought the wireless AP was being overloaded, so

we changed it but the problem remained. When this issue arises, the

server machine freezes on "Loading your settings..." when you attempt

to log in to the server physically. To regain control, the server must

be hard rebooted (reset button on front of case).

 

The network connection itself seems fine as two network switches and

two wireless APs have been used with no resolution to the problem. The

event log shows nothing suspicious other than a few unusual network

disconnections and automatic reconnects.

 

This is a reasonably urgent issue and a speedy response would be

highly appreciated. Thank you in advance.

[jsnetman]

First off I would check for the conficker/downadup virus. Your symtoms are an exact copy of what happened here 2 weeks ago. If you are virus free next step would be to confirm DNS is functioning correctly. Withouts a correct DNS setup your servers will be slow to logon and the clients will not receive GP.

[adrianm83]

I can confirm that we have no reported virus situation. This is a new server only 5 days old. I spent the weekend setting it up and configuring the users and policies.

 

It is a weird situation because the problem it becoming unresponsive seems to only happen once around 6 to 8 clients authenticate. I've tried logging each laptop in one at a time and after about 6 or 7 it seems to just stop there.

 

DNS Seems to be working fine. I can find computer names etc and map to drives. ALthough having said that my knowledge of AD is very limited so could I have confirmation of some settings to check on the DNS side.

 

I had a quick look and clients seems to update their A records ok.

[jsnetman]

Just to confirm you aint got this conficker business download this from symantec and run it on the server and a couple of clients with the switch /nofilescan. W32.Downadup Removal Tool | Symantec

Honestly those symptoms are exactly what we suffered a while ago. Turned out one laptop with conficker caused the whole network to go down.

[adrianm83]

Hi,

 

I have run the tool and everything is clear for teh conflicker virus.

[jsnetman]

When you reboot the server does it take a long time to get to the logon screen?

[adrianm83]

bootup time is normal. Nothing unsual to report there.

[jsnetman]

Hmm strange one. Just to rule out a faulty wireless point you could try hanging the laptops of a switch with a cat5 lead. Just to see if they work from a physical connection.

[adrianm83]

I've ruled out the access point by replacing it with a couple of others yesterday. This did not make a change.

[Techdw]

HAve you tried using new Switchs??

Also what % is the CPU on the server when you connect the laptop and when the laptop stop responding.

 

I had a simliar problem once and it was the switchs.

Edited May 6, 2009 by Techdw

[adrianm83]

The switches are new - replaced last term - Feb I think. There Netgear 24 1gbps. Can't remember the model. I did remove them from the equation and connected the server, 1 desktop and the WAP point to a d-link 8 port switch, yet had the same issue.

[Brpilot99]

Hiyah just a thought .. are your wireless network ip settings pointing at your dns servers IP? ... you have to set these up separatly from the nic settings ...

[adrianm83]

In reference to the IP Settings for WAP, each WAP Point has an individual IP address preset,

 

Then DHCP is issued from the Server it's self.

 

DNS are cofigured as follow

 

192.168.0.1 - for AD Server

192.168.0.6 - Gateway

then 2 external IP address for requests outside of our domain.

 

All these setting are distributed to the laptops successfully.

[Brpilot99]

Hi again .... how about the laptop wireless tcpip dns settings? do they point at your dns server?

[Brpilot99]

Sorry just read your previous again ... have you run ipconfig /all on a laptop and checked that the wireless nic has got your dns servers ip setting ....?

[Techdw]

try a constant Ping -t to see if a connection is breaking down????

[adrianm83]

Thanks for eveyrone's help.

 

Turned put that I had not set the exclusion list in our real-time antivirus protection. Soprted this out and everything is running smoothly!!!

 

 

Many thanks for everyone's help