SNMP Leaks Memory If the OID Cannot Be Decoded

• Microsoft Windows NT Workstation versions 4.0
• Microsoft Windows NT Server versions 4.0

SYMPTOMS

Over time, the Windows NT system responsiveness appears sluggish, and Clients may report a gradual decrease in system performance.

By tracking the amount of Private Bytes for Snmp.exe, it can be observed that, over time, it increases without decreasing. This is viewable using Windows NT Performance Monitor by selecting the following counter to monitor:

   Object: Process
   Instance: SNMP
   Counter: Private Bytes

CAUSE

If SNMP cannot decode an OID from a network packet, SNMP does not free up the memory, resulting in a memory leak in the Snmp.exe processes. The impact of this leak will be more evident on a system running on a network segment that receive lots of SNMP broadcast traffic.

RESOLUTION

To resolve this problem, obtain the following fix or wait for the next Windows NT service pack.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.