As a bit of a tech geek I have a tendency to pick up a variety of pieces of hardware and software to see if they'll be useful on tests. One of my more successful purchases has been a USB powered Ethernet switch that handles PoE pass-through and has a couple of mirrored ports. It's pretty compact so it goes easily in a bag for on-site jobs and can be useful in a number of scenarios
- Lack of Ethernet ports on-site. I've had this on more than one occasion, you get to site and there's no free ports, so a switch and a couple of patch cables can be very handy
- Monitoring Thick Client Apps. Not all apps are particularly proxy friendly, so having an easy way to see all the traffic on the switch is very handy
- VOIP assessments. A standard part of VOIP assessments is looking at the traffic between the phone and the management servers, so having something that supports PoE pass through is handy as that's how most VOIP phones operate.
All-in-all if you're a tester, I'd recommend getting something like this. The one I've got is the Dualcomm DCGS-2005L although I'm sure there's others that meet the bill.