ndpmon

On-link icmpv6 message monitoring and reporting daemon

NDPMon is an equivalent of ArpWatch for IPv6. NDPMon, Neighbor Discovery Protocol Monitor, is a tool working with ICMPv6 packets. NDPMon observes the local network to see if nodes using neighbor discovery messages behave properly. When it detects a suspicious Neighbor Discovery message, it notifies the administrator by writing in the syslog and in some cases by sending an email report.