Dear all,

Here I have a very detailed question and I would like to thank you all for your help in advance.

Some background information first:

Thunder is a very popular P2P file downloading software in China and it is not open sourced. Recently I have been doing some protocol analysis experiments about Thunder by Wireshark. Experiment descriptions are as follows:

Experiment 1 :  Close other applications and run Thunder------I will get a lot of packets with the protocol name as OICQ. (OICQ is a very popular IM soft ware in china but actually during this experiment I did not open it).

Experiment 2:  keeping all other setting unchanged, I  close Thunder, immediately after experiment 1---------Here I did not get any OICQ packets anymore.

Actually I have talk to some guys who work in OICQ company and according to them, Thunder and OICQ are competitors and there are not any co-operations between them.  So I am really confused that how I can capture OICQ packets from Thunder while the OICQ is not running.  Therefore, if it is possible, may I ask how  Wireshark works and decide a packet is an OICQ packet? I mean, besides of the UDP port, are there any other ways for Wireshark to categorise a packet to be an OICQ packet?

Actually I am really confused here and your help will be really appreciated for me.

Thank you in advance and best regards,

Adele JIA