5 segment ip address

i got this strange hit on the firewall. it blocked a 5-segment ip address. normal ip addresses today (ip4) has only 4 segments i.e. 192.168.2.1. the ip6 addressing (5 segments) is not yet in popular use.
either someone out there is using an ip6 address already or the firewall blocked a stupid spoofer/hacker.
har har.
