You’ll use this channel to coordinate your activities and to compare notes.)
Once you’re confident that both computers are talking to each other over the Internet correctly and are saving a valid packet trace, you can begin to gather experimental data about whatever application is of interest to you - or try to reproduce any reported or conjectured errors or problems.
For example, for our tests with Comcast, we configured one of the computers as a BitTorrent tracker and sender and gave the other computer a BitTorrent file instructing it to attempt to download the file hosted by the first computer.
The details of what you’ll test depend on what you’re interested in and will require you to be familiar with the application you’re testing in some detail.
In the BitTorrent example, it’s not sufficient simply to have both parties start running BitTorrent at this point; rather, one computer needs to be configured explicitly to offer a download to the other computer, which, in turn, needs to be configured to request a download from that computer.
When your experiment is complete, you should stop the capture and save the resulting capture files to disk.
You can then exchange these files with the person at the other end - by e-mail, for instance.
Wireshark can be used to open and display a saved capture file generated on another computer.There are many other network analyzers or packet sniffers that could be used instead of Wireshark.