User Guide

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Appendix C. Wireshark Messages
Wireshark provides you with additional information generated out of the plain packet data or it may need
to indicate dissection problems. Messages generated by Wireshark are usually placed in [] parentheses.
C.1. Packet List Messages
These messages might appear in the packet list.
C.1.1. [Malformed Packet]
Malformed packet means that the protocol dissector can't dissect the contents of the packet any further.
There can be various reasons:
• Wrong dissector: Wireshark erroneously has chosen the wrong protocol dissector for this packet. This
will happen e.g. if you are using a protocol not on its well known TCP or UDP port. You may try
Analyze|Decode As to circumvent this problem.
• Packet not reassembled: The packet is longer than a single frame and it is not reassembled, see
Section 7.6, “Packet Reassembling” for further details.
• Packet is malformed: The packet is actually wrong (malformed), meaning that a part of the packet is
just not as expected (not following the protocol specifications).
• Dissector is buggy: The corresponding protocol dissector is simply buggy or still incomplete.
Any of the above is possible. You'll have to look into the specific situation to determine the reason. You
could disable the dissector by disabling the protocol on the Analyze menu and check how Wireshark
displays the packet then. You could (if it's TCP) enable reassembly for TCP and the specific dissector
(if possible) in the Edit|Preferences menu. You could check the packet contents yourself by reading the
packet bytes and comparing it to the protocol specification. This could reveal a dissector bug. Or you could
find out that the packet is indeed wrong.
C.1.2. [Packet size limited during capture]
The packet size was limited during capture, see "Limit each packet to n bytes" at the Section 4.5, “The
"Capture Options" dialog box”. While dissecting, the current protocol dissector was simply running out of
packet bytes and had to give up. There's nothing else you can do now, except to repeat the whole capture
process again with a higher (or no) packet size limitation.
C.2. Packet Details Messages
These messages might appear in the packet details.
C.2.1. [Response in frame: 123]
The current packet is the request of a detected request/response pair. You can directly jump to the
corresponding response packet just by double clicking on this message.
C.2.2. [Request in frame: 123]
Same as "Response in frame: 123" above, but the other way round.