Remember your first networking class, where you had to learn how to calculate network subnet masks and other TCP/IP arcana? Well, now you can do it all from your iPhone. There are a lot of utilities out there that can help you scan your network, including R-U-On and iNet from Banana Glue. (Why do app developers have to adopt the Apple cuteness ethos?) But IPEToolbox goes beyond the basics.
Besides telling you how many nodes on your network is meant by the term "/16," IPEToolbox lets you calculate the optimal subnet size given the number of nodes, or you can find out how to write various allow-and-deny firewall rules in the most concise manner possible. It also has a VoIP bandwidth calculator, which tells you the number of Erlangs for your voice traffic.