OMRON Global builds machines for industrial and manufacturing work. FINS is used to control some of those machines over the network.


Don't know much about the history of the protocol other than locating the manual for this was a major PITA. I would assume that this protocol was originally just a serial connection and has now been overlaid onto UDP.

Protocol dependencies

Example traffic


Omron Header

Command Data


The OMRON-FINS protocol dissector is fully functional to the specification listed in bug 3226. There are a couple things that one might encounter that I know are not supported, but don't have any good documentation on.

1. There is some magic way to encode things using some type of ASCII encoding, but this shouldn't happen when the protocol use UDP. 2. If a PLC implements a command or response code that is outside of the command reference it won't be decoded. 3. If a device specific setting is used for a particular PLC it won't be decoded correctly as those are PLC specific and not documented in the base command reference 4. I'll fix it if anyone can point me to more manuals.

Preference Settings

Currently no preference settings are support or needed. If there are device specific problems found this is probably what needs to be implemented to fix the decoding.

Example capture file

Display Filter

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

Show only the OMRON-FINS based traffic:


Capture Filter


External links


OMRON-FINS is a funny little protocol, I needed this decoder for some specific SCADA work I was doing, so I'm guessing no one will ever need this decoder. But if you do its now here. Also if you ever come across some FINS traffic that isn't decoded correctly please open bugs or point me to pcaps/manuals and I'll update the dissector.

Imported from on 2020-08-11 23:17:38 UTC