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# Kernel Lock Manager Protocol (KLM)
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The KLM protocol is used, in some operating systems, to manage lock requests between the NFS client kernel of a [NFS](/NFS) host and the user space lock manager daemon. This protocol is only used across the loopback interface and will never be seen on a network.
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## History
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This protocol was developed at the same time as [NLM](/NLM) and is semi-similar to [NLM](/NLM).
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## Protocol dependencies
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- [ONC-RPC](/ONC-RPC): KLM uses [ONC-RPC](/ONC-RPC) as its transport mechanism; it runs on top of [ONC-RPC](/ONC-RPC) as program 100020.
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## Example traffic
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XXX - Add example traffic here as plain text or Wireshark screenshot).
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## Wireshark
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The KLM dissector is fully functional.
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## Preference Settings
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There are no preferences for the KLM protocol itself, but since it shares the filehandle structure with [NFS](/NFS) there are some [NFS](/NFS) preferences related to filehandles that do affect the dissection of KLM.
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See [NFS\_Preferences](/NFS_Preferences)
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## Example capture file
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[SampleCaptures/klm.pcap.gz](uploads/__moin_import__/attachments/SampleCaptures/klm.pcap.gz)
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## Display Filter
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A complete list of KLM display filter fields can be found in the [display filter reference](http://www.wireshark.org/docs/dfref/k/klm.html)
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Show only the KLM based traffic:
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```
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klm
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```
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## Capture Filter
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You cannot directly filter KLM while capturing. However, if you know the [UDP](/UDP) port used (see above), you can filter on that one. KLM only exists ontop of the loopback interface so one can only capture KLM on a host that allows capturing of loopback.
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## External links
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A KLM specification does not exist, however most unixen do have an interface specification for the protocol in /usr/include/rpcsvc
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## Discussion
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---
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Imported from https://wiki.wireshark.org/Kernel_Lock_Manager on 2020-08-11 23:15:47 UTC |