Summary: I'm a Microsoft Small Business Specialist and chose the NetTool Pro II for looking at small business networks with only one or two servers. It certainly works well in that environment; as well as being able to sit between a PC and a switch I've used it on a SBS 2003 server LAN connection to the switch to check all traffic out to the internet. In SBS the normal configuration is to pass all internet traffic through the server. I've had it for two months now and have found networks with WINS configuration problems, one where some PCs where using IPX and well as IP, one where a DNS forwarder was set wrong, a switch port that had a low link signal which caused the PC to keep dropping off the network, moved to another port with a normal link level and the problem was gone.
On the down side, it goes through batteries quickly; I would certainly suggest the rechargeable battery option. Even though I registered the instrument with Fluke I had to email them to get the personalization key. Also one seems to have to check for software firmware updates it would be nice if Fluke would email registered owners about updates. The latest update includes port monitoring and I'm just beginning to try that out. Spyware and viruses can be very good at hiding themselves on a PC but at the end of the day they have to go out the network connection to propagate or send information. It will be interesting to see what the port monitor picks up.
One thing I did notice, certainly in the 4.06 software, when set to DHCP it doesn't pick up the connection DNS suffix from the DHCP server so in NetProve you have to put the full DNS name e.g. server.domain.local rather than just server.
Overall very pleased with the instrument.