Wireshark-users: [Wireshark-users] Incorrectly framed messages
From: "Lobb, Janos" <janos.lobb@xxxxxxxx>
Date: Mon, 11 Mar 2013 19:58:02 +0000
Hi,

We have an application that receives TCP messages - HL7 formatted -, into a holding table and processing them later.  We found that because of a bug/limitation in the program it is unable to put together messages that are bigger than 32K.  I understand that the parts above 32K is not shown in the table, but I do not understand why do I not see them in a WS capture.  

The messages contains different segments, like MSH, IN1, IN2, ROL, etc…    There is a server that sends these messages and there is a client that receives them.  My assumption was that even if the bug is in the client program I still should see the above 32K part of the message in wireshark, but I do not.

The message just breaks and the client sends back an ACK message but with some missing IDs, that causes the server to garble up the next message even if that is just a short one.

When I look the Expert Info Composite, I see plenty of Malformed messages, about 15,000 from 540,000, but none of them contains the above 32K part of the incorrectly framed messages.

Any insight ?  Does Wireshark just drops them ?  If yes, is there a setting to force WS to show them even if they are malformed ?

Thanks ahead,

János
P.S.  Now, this "incorrectly framed message" text is put into the error table by the client program, so it is not necessarily a good labeling of the symptom from the networking point of view.