Overview of services running on Port 2121 TCP.
~397 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	Count	Percent
ftp	Netgear broadband router or ZyXel VoIP adapter ftpd	148413	37.364
ftp	Pure-FTPd	57232	14.409
ftp	D-Link DSL-2750U ftp firmware update	36482	9.185
no match	-/-	33578	8.454
ftp	vsftpd	13402	3.374
http		12121	3.052
ftp		11670	2.938
ftp	Microsoft ftpd	8924	2.247
ftp	FileZilla ftpd	8623	2.171
http	CCProxy	7861	1.979
ftp	ProFTPD	7452	1.876
ftp	MikroTik router ftpd	7414	1.867
ssh	OpenSSH	6515	1.64
irc	Dancer ircd	4014	1.011
http	SonicWALL	3647	0.918
ftp	Serv-U ftpd	3602	0.907
chat	AIM or ICQ server	2071	0.521
telnet		1788	0.45
socks-proxy	CCProxy socks proxy	1569	0.395
telnet	Cisco IOS telnetd	1557	0.392
ftp-proxy	Frox ftp proxy	1356	0.341
http-proxy	EZproxy web proxy	1185	0.298
ssl	SSLv3	1095	0.276
ftp	vsftpd (before 2.0.8) or WU-FTPD	954	0.24
http	lighttpd	877	0.221
http	Apache	870	0.219
ftp	oftpd	850	0.214
ftp	DrayTek Vigor router ftpd	845	0.213
ftp	DrayTek Vigor 2820 ADSL router ftpd	755	0.19
telnet	Cisco 1721 router telnetd	750	0.189
http	AIM	606	0.153
ftp	Dreambox ftpd	469	0.118
http	Microsoft IIS httpd	455	0.115
ftp	Synology DiskStation NAS ftpd	435	0.11
ftp	Gene6 ftpd	420	0.106
ftp-proxy	CCProxy ftp proxy	290	0.073
http-proxy	CCProxy http proxy	263	0.066
mongodb	MongoDB	256	0.064
http	WangWnagSimpleServer	212	0.053
http	Gateway-Webs	178	0.045
ftp	bftpd	170	0.043
http	GoAhead-Webs httpd	169	0.043
http	thttpd	161	0.041
http	Microsoft HTTPAPI httpd	158	0.04
http	Httpd	153	0.039
http	Avtech AVN801 network camera	150	0.038
ftp	zFTPServer	136	0.034
http	Boa HTTPd	119	0.03
ssh		114	0.029
http	Netwave IP camera http config	109	0.027
ftp	ZyXEL ZXDSL 831CII ADSL modem telnetd	107	0.027
ftp	WS FTPd	102	0.026
http	Apache Tomcat/Coyote JSP engine	99	0.025
ftp	glFTPd	96	0.024
ftp	FreeBSD ftpd	94	0.024
ftp	Xlight ftpd	90	0.023
ftp	TYPSoft ftpd	87	0.022
ftp	NET Disk/NetStore ftpd	85	0.021
http-proxy	Squid http proxy	76	0.019
ftp	Microsoft IIS ftpd	71	0.018
http	nginx	66	0.017
ftp	Draytek ADSL router ftpd	65	0.016
vnc	VNC	64	0.016
ssh	Dropbear sshd	64	0.016
irc-proxy	psyBNC	64	0.016
ftp	Cerberus FTP Server	59	0.015
http	PDR-M800	58	0.015
http	FC	58	0.015
ftp	ACLogic CesarFTPd	56	0.014
ftp	Comtrend FTP firmware update utility	55	0.014
ftp	Balance Servers TCAdmin game hosting ftpd	55	0.014
sftp	ProFTPD mod_sftp	53	0.013
ftp	Quick 'n Easy ftpd	53	0.013
ftp-proxy	AVM KEN! ftp proxy	51	0.013
http	Rhinosoft Serv-U httpd	50	0.013
telnet	Cisco router telnetd	47	0.012
ftp-proxy	Squid ftp proxy	41	0.01
ftp-proxy	JanaServer ftp proxy	41	0.01
arcserve	ARCserve Discovery	41	0.01
tandem-print	Sharp printer tandem printing	40	0.01
ftp	Titan ftpd	40	0.01
http	uTorrent WebUI	39	0.01
http	Cross Web Server	39	0.01
ftp	GNU Inetutils FTPd	38	0.01
ftp	WU-FTPD	37	0.009
ftp	WinFtpd	37	0.009
http	mini_httpd	36	0.009
telnet	KRASNET!	34	0.009
http	Boa httpd	34	0.009
ftp	pyftpdlib	34	0.009
http	dcs-lig-httpd	33	0.008
http	YAZ Z39.50 http interface	32	0.008
http	GoAhead-Webs	32	0.008
ssl	TLS	31	0.008
http	HttpFileServer httpd	31	0.008
http	GeoVision GeoHttpServer for webcams	30	0.008
http	uc-httpd	29	0.007
http	GoAhead-Webs embedded httpd	29	0.007
ftp	IBM OS/400 FTPd	29	0.007
nntp	INN nntpd	28	0.007
http	Hikvision-Webs	28	0.007
ssh	MikroTik RouterOS sshd	27	0.007
ftp	tnftpd	27	0.007
telnet	Linux telnetd	26	0.007
directconnect	Direct Connect P2P	26	0.007
ftp	ALFTP	24	0.006
ftp	Guild ftpd	23	0.006
mysql	MySQL	22	0.006
ftp	Wing FTP Server	22	0.006
ftp	stupid-ftpd	22	0.006
ftp	AD Network Video Dedicated Micros DVR ftpd	22	0.006
ftp-proxy	kingate ftp proxy	21	0.005
ftp	Sonic FTP Server	20	0.005
ftp	Rumpus ftpd	20	0.005
ftp	DrFTPD	20	0.005
smtp	Microsoft Exchange smtpd	19	0.005
http	DVR Systems webcam http interface	19	0.005
ftp	SwiFTP	19	0.005
ftp-proxy	UserGate ftpd	19	0.005
ftp	Oracle XML DB ftpd	19	0.005
http	MiniServ	18	0.005
http	D-Link DIR-300 WAP http admin	18	0.005
upnp	Portable SDK for UPnP devices	17	0.004
http	uhttpd	17	0.004
http	Mbedthis-Appweb	17	0.004
ftp	Nucleus ftpd	17	0.004
http	Intoto httpd	16	0.004
ftp	SlimFTPd	16	0.004
vnc	RealVNC Enterprise	15	0.004
vnc		15	0.004
ssh	WeOnlyDo sshd	15	0.004
http-proxy	F5 BIG-IP load balancer http proxy	15	0.004
http	Gadspot/Avtech AV787 webcam http config	15	0.004
http	RemotelyAnywhere remote PC management httpd	14	0.004
http-proxy	MikroTik http proxy	14	0.004
http	Draytek Vigor ADSL router webadmin	14	0.004
http	Allegro RomPager	14	0.004
ftp	Synolgy NAS ftpd	14	0.004
ssh	Cisco SSH	13	0.003
rtsp		13	0.003
http	Jetty	13	0.003
ftp	OpenBSD ftpd	13	0.003
ssh	SCS sshd	12	0.003
ssh	Bitvise WinSSHD	12	0.003
smtp	Microsoft ESMTP	12	0.003
smtp		12	0.003
remoting	MS .NET Remoting services	12	0.003
ftp	Solaris ftpd	12	0.003
vnc	RealVNC Personal	11	0.003
http	World Client WDaemon httpd	11	0.003
http	QNAP TS-219P NAS http config	11	0.003
ftp	TRENDnet/Hawking webcam ftpd	11	0.003
smtp	Postfix smtpd	10	0.003
http	httpd	10	0.003
http	AIM HTTP	10	0.003
ftp	WU-FTPD or MIT Kerberos ftpd	10	0.003
ftp	Treck Embedded ftpd	10	0.003