Wireshark-users: [Wireshark-users] Determining SMB client/server from traffic

From: Rayne <hjazz6@xxxxxxxxx>
Date: Wed, 28 Nov 2012 17:46:39 -0800 (PST)
Hi,

I have a PCAP file that contains some SMB traffic showing the file transfer from one PC to another. I'm trying to determine which is the PC that initiates the file transfer. From Wireshark, I have the following packets.
NT Create Andx Request, FID: 0x4007, Path: \abc.txt (1.1.1.1:49752 -> 2.2.2.2:445)
NT Create Andx Response, FID: 0x4007 (2.2.2.2:445 -> 1.1.1.1:49752)
...
Read Andx Request, FID: 0x4007, 32768 bytes at offset 0 (1.1.1.1:49752 -> 2.2.2.2:445)
Read Andx Response, FID: 0x4007, 32768 bytes (2.2.2.2:445 -> 1.1.1.1:49752)
...
I thought 1.1.1.1 was the one that started the file transfer to 2.2.2.2, since 1.1.1.1 is the one requesting and 2.2.2.2 is the one responding. But in the Read Andx Response packet, I see the contents of the file being transferred. That confused me because if those packets are carrying the file contents, doesn't that mean 2.2.2.2 is the one transferring the file to 1.1.1.1?

Thank you.

Regards,
Rayne