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Wireshark Not Automatically Recognizing Some Modbus Traffic

asked 2022-06-17 14:38:15 +0000

What would cause Wireshark to not automatically recognize and decode Modbus TCP traffic? If I force it using Decode As and a port everything seems to look fine. The traffic appears to be compliant with the Modbus 1.1b specification.

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answered 2022-06-17 18:24:43 +0000

grahamb gravatar image

updated 2022-06-17 18:40:36 +0000

The Modbus dissector is not heuristic so relies on traffic either running on the "standard" ports 502/tcp, 502/udp, 802/tls or the user configuring the dissector preferences for the port(s) actually used or using "Decode As..."

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Asked: 2022-06-17 14:38:15 +0000

Seen: 125 times

Last updated: Jun 17 '22