Packet Tracer fails with “ERROR: TRACER: NP failed tracing packet”

If you are getting this error message when trying to do packet tracer you hit a bug CSCvi37889.

asa/pri/act# packet-tracer input inside tcp 10.1.0.10 1235 8.8.8.8 443 detailed
ERROR: TRACER: NP failed tracing packet

You can get this fixed by removing existing captures on your firewall.

First check if any captures exist:

asa/pri/act# sh cap

capture capout type raw-data interface outside [Buffer Full – 524138 bytes]
match ip host 208.172.16.78 host 208.183.87.46
capture asp type asp-drop all circular-buffer [Capturing – 523926 bytes]

Remove them:

no cap capout

no cap asp

Run your tracer again:

asa/pri/act# packet-tracer input inside tcp 10.1.0.10 1235 8.8.8.8 443 detailed

Phase: 1
Type: ACCESS-LIST
Subtype:
Result: ALLOW
Config:
Implicit Rule
Additional Information:
Forward Flow based lookup yields rule:

If it runs you are good. Otherwise you need to reload your box.

Additionally, good rule of thumb is to ALWAYS remove your captures once you are done. No reason to hug the buffer.

Regards,

Bart

Reference:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvi37889/?rfs=iqvred