Overview of services running on Port 1720 TCP.
~26 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
no match						7761	28.941
H.323-gatekeeper	GNU Gatekeeper					6277	23.407
irc	Dancer ircd					2883	10.751
H.323/Q.931						2591	9.662
ms-wbt-server	Microsoft NetMeeting Remote Desktop Service			Windows		1930	7.197
H.323-gatekeeper	CompTek AquaGateKeeper					1823	6.798
chat	AIM or ICQ server					1114	4.154
ms-wbt-server	Microsoft Terminal Service		Used with Netmeeting, Remote Desktop, Remote Assistance	Windows		850	3.17
ms-wbt-server	Microsoft Terminal Service			Windows		404	1.507
http	WangWnagSimpleServer	1.0				213	0.794
http	Microsoft IIS httpd					120	0.447
http	Microsoft HTTPAPI httpd	2.0	SSDP/UPnP	Windows		74	0.276
socks5			GSSAPI authentication required			59	0.22
ssh			protocol 1.5			55	0.205
http						44	0.164
ssh	OpenSSH	4.3	protocol 2.0			41	0.153
telnet						38	0.142
socks5						30	0.112
arcserve	ARCserve Discovery					28	0.104
ms-wbt-server-proxy	nmproxy NetMeeting proxy					27	0.101
http	Boa HTTPd	0.94.14rc21				27	0.101
vnc	VNC		protocol 3.8			25	0.093
ftp						20	0.075