Good luck to us all.
I downloaded Wireshark 1.8.2 (first time I've used one of these) and captured some interactions with the server, including collecting a few items from the auction house, cancelling and placing new bids, starting and aborting a Ouro flashback, and running one ITF.
It may have been my newbieness, or maybe filtering works differently in different Wireshark versions - anyway, I ran into a few minor problems. Here's what I did to resolve them:
1) It wasn't obvious how to apply a Capture Filter, and Help was less than helpful. I thought that the "capture filters" button in the toolbar would do the job but it had no effect besides allowing me to create a new filter - all the traffic to unrelated ip addresses still showed up.
Solution: double-click on the name of the capture interface in the list below "Start" or in the list of interfaces which appears after you click on "Capture Options". There is a place to enter a capture filter string, however...[see problem #3]
2) Due to my initial failure above, I then tried a display filter. This at least worked intuitively. I created and saved the filter, which made a nice clickable toolbar button, and could apply it and clear it. However, it wasn't completely filtering out the traffic to unrelated ip addresses.
Solution: I used the display filter "(ip.src >= 64.25.32.0 and ip.src < 64.25.48.0) or (ip.dst >= 64.25.32.0 and ip.dst < 64.25.48.0)" instead.
3) Since the display filter was hiding instead of actually eliminating the unrelated traffic, I went back to working on problem #1, at which point I found its solution, but encountered another problem. When I tried the suggested string "ip.addr >= 64.25.32.0 and ip.addr < 64.25.48.0", it complained about an invalid capture filter syntax; my display filter string also failed to work. After a bit of searching, I found that capture filters and display filters work differently, and I made a new capture filter string "net 64.25.0.0 mask 255.255.0.0" which seemed to work. Maybe someone who knows Wireshark better than me can point where I went wrong at first, or make an even better capture string.
Hope this helps other Wireshark newbies.