When I generate UDP traffic with STC4.42, in wireshark I see BAD UDP Letgth. Why ?
I attched packet editor and wireshark screenshot.
The frame configuration doesn't appear to have an actual UDP header configured. Setting the IPv4 protocol field value to UDP will not automatically add the UDP header into the frame configuration.
From the packet capture, the data after the IPv4 header is the fill pattern. Hence, the UDP frame length decoded by wireshark is incorrect.
In STC how I can add/edit UDP or TCP header to packets?
Can you explain more about second sentence, is wiresharak decoding incorrect?
In the StreamBlock editor in the Frame tab (the picture you posted of the editor), click on "Add Header(s)" under the "Actions" section on the left hand side. The list of available headers will show up including TCP or UDP (should be under the IP category, if I remember correctly).
Wireshark is correctly identifying the field length as bad based on the expectation that an actual UDP header is after the IPv4 header in the frame. It expects a UDP header to be present since the protocol field in the IPv4 header is set to UDP. The correct value of the UDP length field should be size of the UDP header + payload.
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