What are some alternatives?
When comparing Arpwatch and Netcut Defender, you can also consider the following products
TuxCut - TuxCut is a netcut "in Windows OS" like software written in PyQt.
NetCut - NetCut is a Software that helps you admin your network by purely on ARP protocol.
CSArp-Netcut - An arpspoofing program that lets users launch spoofed arp requests to disrupt connections in a LAN
WifiKill - App with ability to block other devices from network
ARP Monitor - Keeps a record of ARP traffic in realtime with a log of changes and new addresses and IP mappings.
Wireshark - Wireshark is a network protocol analyzer for Unix and Windows. It lets you capture and interactively browse the traffic running on a computer network.