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Dns.exe consuming a large amount of nonpaged pool memory and file handles



Article Summary: Poor server performance occurs or the operating system becomes unresponsive on servers running Microsoft Windows Server that have the DNS Server role installed due to changes to file handle and nonpaged pool memory usage by Dns.exe


Issue

A Windows server hangs, reboots, becomes unresponsive or network clients disconnect due to Dns.exe consuming a large amount of nonpaged pool memory and file handles.

Solution:

Log on to the server using the local or domain Administrator account, open an elevated command prompt and perform the following steps.

1. Press the Windows Logo+R, type runas /user:administrator@domain.local cmd where domain.local is replaced by the name of the Active Directory domain or local server name and press Enter. The same task can be accomplished using the Command Prompt and Run as Administrator.

2. Type the Administrator account password when prompted and press Enter.

3. Type dnscmd.exe /config /socketpoolsize 1000 and press Enter.

4. Type net stop dns && net start dns and press Enter.




Additional Information:

This information pertains to Windows Server 2003, Windows Server 2003 R2, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012 and Windows Server 2012 R2.

Microsoft released security bulletin MS08-037 in July of 2008 for Windows Server 2003. The bulletin contains important information about vulnerabilities in the Windows Domain Name System (DNS) that could allow spoofing specifically those posed by the Kaminsky vulnerability. Windows DNS now uses source port randomization instead of a predictable and known port. The ports are configurable through registry settings and the pool size is configurable through a registry setting or using Dnscmd.exe.

Windows servers already experiencing heavy loads of non-paged pool memory may be impacted further by the installation of the Windows 2003 updates listed below or Windows servers running newer versions of Windows.

DNS Client (951748)
DNS Server (951746)

The installation of the updates in Windows 2003 causes Dns.exe file handles to climb above 5000 and increased non-paged pool memory consumption. This can cause servers to hang, reboot or become unresponsive and often client computers lose network connectivity to the server. A reboot will resolve the issue for periods or time, but the issue will generally resurface in two to seven days. The workaround is to reduce the number of sockets thereby reducing the number of file handles and nonpaged pool memory consumption. 32-bit operating systems are more prone to the negative affects of this issue. Refer to this KB article for further information.

Installation of the Windows 2003 SP1 or SP2 Support Tools is required when using Dns.exe. The tools may be found at the following locations.

Windows 2003 SP1 Support Tools

Windows 2003 SP2 Support Tools

The problem can be identified by reviewing the file handles and non-paged memory consumption in Windows Task Manager or in the Processes section of a DSET.

Perform the following using Task Manager in Windows Server 2003, Windows Server 2003 R2, Windows Server 2008 and Windows Server 2008 R2.

1.Open Task Manager by right clicking in the task bar area and choosing Task Manager.

2. Click the Processes tab.

3. Click View then Select Columns.

4. Check Non-paged Pool and Handle Count for Windows 2003 or Memory - Non-Paged Pool and Handles for Windows Server 2008.

5. Select OK.

6. Click on the Handles column twice to sort by highest handle count.

Perform the following using Task Manager in Windows Server 2012 or Windows Server 2012 R2.

1. Open Task Manager by right clicking in the task bar area and choosing Task Manager.

2. Click the Details tab.

3. Hover the mouse over a column name and right-click and choose Select Columns.

4. Check NP Pool and Handles.

5. Select OK.

6. Click on the Handles column twice to sort by highest handle count.

Windows Task Manager prior to implementing the solution.



Windows Task Manager after implementing the solution.






Quick Tips content is self-published by the Dell Support Professionals who resolve issues daily. In order to achieve a speedy publication, Quick Tips may represent only partial solutions or work-arounds that are still in development or pending further proof of successfully resolving an issue. As such Quick Tips have not been reviewed, validated or approved by Dell and should be used with appropriate caution. Dell shall not be liable for any loss, including but not limited to loss of data, loss of profit or loss of revenue, which customers may incur by following any procedure or advice set out in the Quick Tips.

Article ID: SLN289347

Last Date Modified: 08/27/2014 08:44 AM


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