Sudden loss of connectivity in our SBS 2011 domain in our company!!!

[SWAMINATHAN SHANMUGAM]

Hi

In our company we are having one windows sbs 2011 domain controller and around 50 pcs with windows xp professional sp3 and some laptops with windows 7 professional sp2; Antivirus is symantec endpoint protection loaded in separate pc made server and all are configured ;working perfectly until today afternoon.

All of a sudden lot of calls started coming to IT ROOM complaining about the lost of connection between dc and the clients.We checked the pc's in our IT ROOM for myself and colleague starting to troubleshoot from our pc's since we also lost the connectivity.

* ping not working from any pc to dc

* ping not working with default gateway from the pc's lost connection

*layer 2 connectivity is ensured OK by connecting my pc through live bootcd and ping works with dc,gateway ;I opted for live boot cd since I rebooted my pc and the dc couple of times ;no effect

*default gateway which is our ADSL ROUTER LAN IP is pinging from the DC and internet is working

*DC'S antivirus symantec endpoint protection is stand alone not in sync with the symantec server... and also a client pc which is loaded with kaspersky antivirus also having the same problem....so  symantec endpoint protection server possibility can be isolated.

* Restarted the DC  and chose last known good configuration also ; same symptom

* found one windows server 2003 loaded as a member server in the domain still working; pinging with the dc;able to access the folders in DC ; afraid to restart and check since on windows xp pc after restarting ; lost the connectivity

N.B: all the clients are getting IP from dhcp in DC

When pinging request timed out is the result and the gpresult of the client pc's give generic failure


The current problem is temporarily solved !!!

I need a permanent solution.

The full details are at  http://social.technet.microsoft.com/Forums/en-US/smallbusinessserver/thread/c2f80047-cc73-43ae-9b4d-a7e3d9354ac5  where I posted this issue first

Thanks & Regards

S.Swaminathan

[SWAMINATHAN SHANMUGAM]

Hi !

Anybody there to help!!!!!