Summary of packet-tracking techniques

Tracking the packet tracking

We just covered a couple ways to track packets in the kernel debugger.  Here’s a quick reference table to help you understand how these techniques fit into your toolbelt.

!ndiskd.pendingnbls !ndiskd.nbl -log
Documentation Here Here
Finds “lost packets” Yes No
Finds “smuggled packets” No Yes
Finds use-after-free No Yes
Loses data if ringbuffer wraps around No Yes
Number of historical events recorded 1 Many (depends on size of ringbuffer)
Records NBL ownership Yes Yes
Records NBL allocation/free No Yes
Records NBL clone/fragment No Yes
CPU performance impact Negligible Approx 3x CPU usage
Memory footprint impact None 32kb – 32mb, depending on RAM size
Enabled by default on client SKU Yes No
Enabled by default on server SKU No No
Enabled when TrackNblOwner is at least... 1 3
Minimum operating system version Windows 7 SP1 or
Windows Server 2008 R2 SP1
Windows 8 or
Windows Server 2012
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