Loss of Network Connectivity

[dnavekar]

Hi Guys,

 

I have 3 PC's in a seperate building from the main school. All 3 have suddenly decided to ages starting up and logging in. When eventually logged in there is no drive access or internet access.

 

I have checked leads, swapped out machines, checked for conflicts on IP, checked networked adapter settings (adapter settings show a successful connection) and IE connections, and tried both to automatically detect and static IP's. The machines are in the right GP's. No changes to the system has been made what so ever yesterday or this morning when everything was working fine. I do at times get the "limited or no connectivity" symbol in the systems tray. The PC's can ping the Server, but when pinging the PC's from the Server, replies are delayed.

 

Any ideas? I hope you can help!

[mac_shinobi]

What switches or network equipment are in between the server and those clients ?

 

Managed / un-managed switches ?

 

Presume no hubs ?

 

What OSes are the 3 pc's ? windows xp / windows 7 ?

 

If windows 7 - what firewall profile are you using or are selected ? If you disable windows firewall does this help at all or make no difference ?

 

last resorts

 

1. reset tcp/ip stack --> How to reset Internet Protocol (TCP/IP)

 

2. Reset winsocks ( winsock catalog) --> Repair/Reset Winsock settings

 

OR Repair and Reset Windows Vista TCP/IP Winsock Catalog Corruption « My Digital Life

 

3. Reset or restore the host file to defaults --> How to Reset Hosts File to Default in Windows XP, Vista and 7? - Tweaking with Vishal

 

Some possible options - also update the network card driver to the latest revision / version ( either from the manufactur of the machine / computers website or from the network card vendor )

 

IE if the PC is made by HP or toshiba / Lenovo or whoever, try the network card driver from there site first ( although I sometimes find there driver is out of date a bit ) so I also try the network card vendors site ie Intel / Marvel Yukon / Broadcomm etc ??

Edited February 19, 2013 by mac_shinobi

[dnavekar]

Hey Shinobi, thanks for the speedy response. All of the clients are running XP via Server 2008 through unmanaged switches. There are is a wireless hub in this area which is not working as well.

 

The PC's are NECs, about 4 years old now. I'll give the options provided a try and let you know how it goes! Wish me luck!

[Davit2005]

Could be some sort of network cabling fault. I had an issue like this that turned out to be a faulty cable but only effected one pc.

 

1. Move one of the PC's to an area where you are having no issues to confirm an issue with the workstation does not exist and move back to make sure.

 

2. Try taking a machine off the domain and then put it back on.

 

What connections have you got to the buildings? Could be a faulty switch, check for any networking cable loops as well by disconnecting and checking switch activity.

[dnavekar]

Hey Shinobi, I've given those fixes a try and I'm still in the same boat. Log in times are incredibly long.

 

Hi Davit, I took one of the machines out and plugged into our ICT Suite which booted up fine. I'm just removing them from the domain to put them back, I'll let you know how it goes.. Cheers

[dnavekar]

Hi Davit, just tried those bit, no luck.. There should not be any problems with the the cables as it's a new building and no changes have been made. I'll try switching ports on the switches if that helps.

 

There is a wifi hub in the middle of these three classrooms which oddly enough is working! I've tested that port with the PC but that does not work either!

[dnavekar]

I seem to have have found a temporary fix for the issue. I moved the affected PC's out of there AD Groups into another. We have an AD Group for ICT Suite PC's and Classroom (Staff) PC's. I moved the clients from the Classroom Group to the Suite Group which worked. The clients are running slower than normal in terms of loading software but shared drive and internet access has returned.

 

Some root cause analysis is required and I need to figure out how to speed up those particular machines! Always a burning fire..

[Davit2005]

I seem to have have found a temporary fix for the issue. I moved the affected PC's out of there AD Groups into another. We have an AD Group for ICT Suite PC's and Classroom (Staff) PC's. I moved the clients from the Classroom Group to the Suite Group which worked. The clients are running slower than normal in terms of loading software but shared drive and internet access has returned.

 

Some root cause analysis is required and I need to figure out how to speed up those particular machines! Always a burning fire..

 

I'd try logging on locally and stopping all non-Microsoft/essential services on just one of the machines. But be carefull, stop services that look rather unusual or installed for a specific software. Do one machine at a time if there aren't that many, you could break something crucial.

[MatthewL]

Update nic drivers

 

Move pc to other side of school which is ok and see if it plays up there

 

Test network cables and between wall port and patch panel in cabinet

 

Just a few things.

[ricki]

Hi

 

Have you sniffed the traffic in the switch with a problem looking for broadcasts.

 

Have you created another ou and added one policy at a time youight have a corrupt policy.

 

Have you got a loop check for flashing lights on switch.

 

Have you rebooted the switch.

 

Have you tried updating the firmware on the switch.

 

Have you done a dvdiag and a netdiag on the servers

 

Richard

[dnavekar]

Hi Guys.. many thanks for your input and I'll be giving these a go shortly. A new networked printer has arrived and requires configuration..

 

Davit - Logging in locally takes longer than normal, there's only three machines but I'll have a look for anything unusual.

 

Matthew - We use exactly the same clients all over the school with the same NIC cards. I have not ran any updates on those and they seem to be working fine. I have swapped out one of the clients and it work on main site fine. I have not tried swapping cables from the patch panel to the ports, this is worth a try.

 

Ricki - I've not tried sniffing the traffic in the switch. To be honest I don't know how to that and will have to turn to the power of google. That's a good point with creating a new OU and adding policy one at a time. The thing is I have other clients in this group without the connectivity issue. I need to do the loop check. The new switch was'nt installed by myself but by an external party. I'll need to check model for exact specs for updates. I've not done a dvdiag and netdiag on the servers before and not sure what I'd be looking for. What should I be seeing?

 

Thanks again guys, your help is much appreciated!

[mac_shinobi]

On the problematic machines. Are there any logs. Control panel -> administrative tools -> event viewer

 

that may help pin point the issues ?

[dnavekar]

I know this one of the obvious ones to check, which I haven't got round to just yet! Terrible.. I'll let you know what gets picked up.

 

On the problematic machines. Are there any logs. Control panel -> administrative tools -> event viewer

 

that may help pin point the issues ?