There has been a few thread discussing Taps, so here is some good write ups on how to build one for yourself:
Passive network tap {HackaDay}:
Make a Passive Network Tap {Instructables}:
Construction and Use of a Passive Ethernet Tap {IBM}:
Of course, if you really wanted to have some fun, go to Wal-Mart late at night and ask the greeter if they could help you find trashbags, roll of carpet, rope, quicklime, clorox and a shovel. See if they give you any strange looks. --Streaker69
I have built a couple of the third design. They work well.
Thorn
Stop the TSA now! Boycott the airlines.
A third party security audit is the IT equivalent of a colonoscopy. It's long, intrusive, very uncomfortable, and when it's done, you'll have seen things you really didn't want to see, and you'll never forget that you've had one.
Of course, if you really wanted to have some fun, go to Wal-Mart late at night and ask the greeter if they could help you find trashbags, roll of carpet, rope, quicklime, clorox and a shovel. See if they give you any strange looks. --Streaker69
I think the biggest issue that I think those making them fail to understand is you don't need to put the taps in the middle of the wire. If you look at the pictures I previously posted, the taps are just extensions of the passthru. There's no reason to put them in the middle like most other things show. Electrically, putting them in the middle or how I did it, it's exactly the same, except the way I did it, it's cleaner and easier to work with.
A third party security audit is the IT equivalent of a colonoscopy. It's long, intrusive, very uncomfortable, and when it's done, you'll have seen things you really didn't want to see, and you'll never forget that you've had one.