We have two separate locations that are having the same symptoms after we recently added the first Server 2008 box on their network. One network has one SBS 2003 server, the other has one Server 2003 Standard and one Server 2000 Standard. At both locations the new Server 2008 machine is a second domain controller and second DNS server.
At both locations network shares work as expected for a while (normally around 8-12 hours) then suddenly any/all drives mapped to them give the following error when the client (XP Pro SP3 and Server 2003/2000) tries to open them:
X: is not accessible.
The network path was not found.
Trying to remap drives or browsing to \\servername\sharename using the name or the IP gives the same network path was not found error.
The only fix we have found is to reboot the Server 2008 box then drive mapping works as expected although a few times we have had to wait 10 minutes or so (AD synch??) after the reboot before drives could be mapped. Everything is then fine for another X amount of hours&
We have not found anything useful in any of the event logs.
Disabling AV (Symantec Corporate 10.x at one location and Symantec Endpoint Protection at the other) had no impact.
This fix did nothing:
Disable Denial-Of-Service attack detection
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then click the following registry subkey:
On the Edit menu, point to New, and then click DWORD Value.
Type DisableDos for the name of the DWORD value, and then press ENTER.
Right-click DisableDos, and then click Modify.
In the Value data box, type 1 to disable denial of service attack detection, and then click OK.