Overview of services running on Port 500 UDP.
~876 Thousand IP addresses observed from May to December 2012
To get raw lists of the data go to Download. For an explanation of what this data is and how it was obtained, see Paper.

Servicename	Product	Version	Info	OS	Devicetype	Count	Percent
isakmp						689589	78.717
no match						97172	11.092
ericssontimestep	Ericsson Timestep Permit VPN					79078	9.027
http	lighttpd	1.4.19				9462	1.08
socks5						433	0.049
netbios-ssn						141	0.016
utorrent-udp	uTorrent UDP listener			Windows		103	0.012