Sure, something like LittleSnitch on the Mac is an interactive and easy-to-use firewall. But I'm really after something that is looking for things you could write easy filters for:
- Tell me whenever something that looks like an email address is sent in the clear
- Tell me whenever my name/postcode/other user-specifiable text is sent in the clear
- Tell me when I'm connect to an SSL site but the hostname is leaked
- Keep a list of DNS entries that I'm leaking
The real challenge will not be to capture everything, it'll be trying to show up items of interest.
- Tell me whenever something that looks like an email address is sent in the clear
- Tell me whenever my name/postcode/other user-specifiable text is sent in the clear
- Tell me when I'm connect to an SSL site but the hostname is leaked
- Keep a list of DNS entries that I'm leaking
The real challenge will not be to capture everything, it'll be trying to show up items of interest.