Don't worry about what I said about hooking the adaptor. If sygate does what you want, then it will do all that low-level work automatically and you won't need to know a thing about it.
For pure interest's sake, I guess I'll explain hooking - even if you may never use this information:
Data gets passed from your cable line to your ethernet card. Then it is passed to your ethernet adapter, then to the operating system, then to the relevent program.
When you "hook" something, you insert yourself into the chain of events so that it would be like this:
Data gets passed from your cable line to your ethernet card. Then it is passed to your ethernet adapter, then it is passed to the hooking program, then the program may CHOOSE to pass it to the operating system, which will then be passed to the relevent program.
So by hooking into the chain of events, you may log or even filter the pass-thru data.
This is how software firewalls block connectivity.