If i'm right u only wanna capture all packets, the Client sends at another local machine which shouldn't be to hard.
First u need to redirect ur clients data to the ip, ur second pc have...
Thenafter ur client, based on the first pc, will timeout within 1000ms, but still sends packets to ask for the server, i think.
If u now use any ethernet sniffer, u might be able to catch what u are searching for ...
Maybe this link gives u an idea:
But at least WPE is recording the same data i thought ..
.. just my opinion ^^