Internet Security Association and Key Management Protocol (ISAKMP)

The ISAKMP protocol is defined in RFC 2408. It is also commonly called Internet Key Exchange (IKE)

This page is very much a stub! Please help expand it.


XXX - add a brief description of ISAKMP history

Protocol dependencies

  • UDP: Typically, ISAKMP uses UDP as its transport protocol. ISAKMP traffic normally goes over UDP port 500, unless NAT-T is used in which case UDP port 4500 is used.

Example traffic

XXX - Add example decoded traffic for this protocol here (as plain text or Wireshark screenshot).


The ISAKMP dissector is (fully functional, partially functional, not existing, … whatever the current state is). Also add info of additional Wireshark features where appropriate, like special statistics of this protocol.

Preference Settings

(XXX add links to preference settings affecting how ISAKMP is dissected).

Example capture file

XXX - Add a simple example capture file to the SampleCaptures page and link from here (see below). Keep this file short, it's also a good idea to gzip it to make it even smaller, as Wireshark can open gzipped files automatically.

Display Filter

A complete list of ISAKMP display filter fields can be found in the display filter reference

Show only the ISAKMP based traffic:


Capture Filter

You cannot directly filter ISAKMP protocols while capturing. However, if you know the UDP port used (see above), you can filter on that one.

Capture only the ISAKMP traffic over the default port (500):

 udp port 500 

External links

  • RFC 2408 Internet Security Association and Key Management Protocol (ISAKMP).


There are some Vendor IDs missing from the filter implementation. It would be great if someone could add them. Identified so far:

  • 0x12F5F28C457168A9702D9FE274CC0100 - Cisco Unity

  • 0xA46AA082D563C4A5FA7F45E5D10FF095 - Unknown

Imported from on 2020-08-11 23:20:23 UTC