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	Version	Count	Percent
ftp	Netgear broadband router or ZyXel VoIP adapter ftpd	1.0	148413	37.364
ftp	Pure-FTPd		57231	14.408
ftp	D-Link DSL-2750U ftp firmware update		36482	9.185
no match	-/-	-/-	33578	8.454
ftp	vsftpd	2.0.8 or later	13233	3.332
http			12121	3.052
ftp			11670	2.938
ftp	Microsoft ftpd		8556	2.154
http	CCProxy		7861	1.979
ssh	OpenSSH	4.3	4941	1.244
irc	Dancer ircd		4014	1.011
http	SonicWALL		3647	0.918
ftp	FileZilla ftpd	0.9.40 beta	2955	0.744
chat	AIM or ICQ server		2071	0.521
ftp	Serv-U ftpd	6.4	1832	0.461
telnet			1788	0.45
socks-proxy	CCProxy socks proxy		1569	0.395
telnet	Cisco IOS telnetd		1557	0.392
ftp	ProFTPD	1.3.3c	1503	0.378
ftp	FileZilla ftpd	0.9.41 beta	1365	0.344
ftp-proxy	Frox ftp proxy		1356	0.341
http-proxy	EZproxy web proxy		1185	0.298
ftp	MikroTik router ftpd	5.14	1133	0.285
ssl	SSLv3		1095	0.276
ftp	FileZilla ftpd	0.9.37 beta	1005	0.253
ftp	vsftpd (before 2.0.8) or WU-FTPD		954	0.24
ftp	ProFTPD	1.3.4a	900	0.227
ftp	oftpd		850	0.214
ftp	DrayTek Vigor router ftpd	1.0	845	0.213
ftp	ProFTPD		834	0.21
ftp	DrayTek Vigor 2820 ADSL router ftpd	1.0	755	0.19
telnet	Cisco 1721 router telnetd		750	0.189
ftp	FileZilla ftpd	0.9.34 beta	707	0.178
ftp	FileZilla ftpd	0.9.39 beta	690	0.174
http	AIM	1.0	606	0.153
ftp	ProFTPD	1.3.1	589	0.148
ftp	ProFTPD	1.3.3a	578	0.146
ftp	MikroTik router ftpd	3.30	567	0.143
ftp	ProFTPD	1.3.2e	546	0.137
ftp	ProFTPD	1.3.2c	486	0.122
ftp	FileZilla ftpd	0.9.31 beta	483	0.122
ftp	Dreambox ftpd		469	0.118
ftp	Serv-U ftpd	6.0	464	0.117
ftp	MikroTik router ftpd	5.7	462	0.116
ftp	Synology DiskStation NAS ftpd		435	0.11
ftp	MikroTik router ftpd	2.9.27	419	0.105
http	lighttpd	1.4.29	418	0.105
ssh	OpenSSH	5.8p1-hpn13v10	413	0.104
http	lighttpd	1.4.19	404	0.102
ftp	MikroTik router ftpd	5.18	369	0.093
ftp	FileZilla ftpd	0.9.33 beta	367	0.092
ftp	Microsoft ftpd	5.0	363	0.091
ftp	Serv-U ftpd	6.3	338	0.085
ftp	MikroTik router ftpd	5.11	312	0.079
ftp	FileZilla ftpd	0.9.36 beta	305	0.077
ftp	MikroTik router ftpd	4.17	300	0.076
ftp	MikroTik router ftpd	5.12	296	0.075
ftp	MikroTik router ftpd	4.11	295	0.074
ftp-proxy	CCProxy ftp proxy		290	0.073
http-proxy	CCProxy http proxy		263	0.066
http	Apache	2.2.3	258	0.065
ftp	MikroTik router ftpd	5.17	249	0.063
ftp	ProFTPD	1.3.0	247	0.062
http	Microsoft IIS httpd	6.0	246	0.062
ftp	MikroTik router ftpd	5.15	246	0.062
ftp	MikroTik router ftpd	5.16	237	0.06
ftp	Gene6 ftpd	3.10.0 build 2	235	0.059
ftp	MikroTik router ftpd	5.8	221	0.056
ftp	ProFTPD	1.3.3d	216	0.054
http	WangWnagSimpleServer	1.0	212	0.053
ftp	MikroTik router ftpd	5.6	210	0.053
ftp	MikroTik router ftpd	5.2	210	0.053
ftp	MikroTik router ftpd	5.5	199	0.05
ssh	OpenSSH	5.3	187	0.047
ftp	Serv-U ftpd	6.2	187	0.047
ftp	ProFTPD	1.3.2	187	0.047
http	Gateway-Webs		178	0.045
ftp	ProFTPD	1.3.3g	178	0.045
ftp	ProFTPD	1.3.3e	176	0.044
ssh	OpenSSH	3.9p1	175	0.044
http	GoAhead-Webs httpd		169	0.043
ftp	ProFTPD	1.3.3	168	0.042
ftp	MikroTik router ftpd	5.9	164	0.041
ftp	ProFTPD	1.3.4	160	0.04
http	Microsoft HTTPAPI httpd	2.0	158	0.04
ftp	FileZilla ftpd	0.9.24 beta	154	0.039
http	Httpd	1.0	153	0.039
http	Avtech AVN801 network camera	1.0	150	0.038
ftp	MikroTik router ftpd	4.16	142	0.036
ftp	MikroTik router ftpd	4.10	136	0.034
ftp	FileZilla ftpd	0.9.32 beta	133	0.033
http	Microsoft IIS httpd		131	0.033
ftp	MikroTik router ftpd	5.13	126	0.032
ssh			114	0.029
http	Netwave IP camera http config		109	0.027
ftp	ZyXEL ZXDSL 831CII ADSL modem telnetd	1.0	107	0.027
http	Apache		106	0.027
ftp	ProFTPD	1.3.3rc4	100	0.025
http	Apache Tomcat/Coyote JSP engine	1.1	99	0.025
ftp	FreeBSD ftpd	6.00LS	94	0.024
http	Apache	2.2.8	93	0.023
ftp	glFTPd	2.01	91	0.023
ftp	MikroTik router ftpd	4.5	90	0.023
ftp	MikroTik router ftpd	4.14	90	0.023
ftp	ProFTPD	1.3.2b	86	0.022
ftp	NET Disk/NetStore ftpd		85	0.021
ssh	OpenSSH	5.9p1-hpn13v11	84	0.021
ftp	ProFTPD	1.3.4rc2	84	0.021
ftp	ProFTPD	1.2.10	82	0.021
http	Apache	2.2.14	81	0.02
ftp	Serv-U ftpd	6.1	81	0.02
ftp	MikroTik router ftpd	2.9.6	78	0.02
ftp	MikroTik router ftpd	5.4	77	0.019
ftp	MikroTik router ftpd	3.20	75	0.019
http	Boa HTTPd	0.94.14rc21	73	0.018
ftp	Microsoft IIS ftpd		71	0.018
ssh	OpenSSH	4.6	70	0.018
ftp	FileZilla ftpd	0.9.27 beta	68	0.017
ftp	FileZilla ftpd	0.9.23 beta	68	0.017
ftp	bftpd	1.6.6	68	0.017
ftp	FileZilla ftpd	0.9.29 beta	67	0.017
ftp	Draytek ADSL router ftpd		65	0.016
vnc	VNC		64	0.016
ftp	Gene6 ftpd	3.9.0 build 2	64	0.016
ftp	FileZilla ftpd		63	0.016
ftp	Gene6 ftpd	3.8.0 build 34	61	0.015
http	thttpd	2.24	59	0.015
ftp	Cerberus FTP Server		59	0.015
irc-proxy	psyBNC	2.3.1	58	0.015
http	PDR-M800	1.0	58	0.015
http	FC		58	0.015
ftp	ACLogic CesarFTPd	0.99g	56	0.014
mongodb	MongoDB	39	55	0.014
ftp	ProFTPD	1.2.10rc3	55	0.014
ftp	Comtrend FTP firmware update utility		55	0.014
ftp	Balance Servers TCAdmin game hosting ftpd		55	0.014
ftp	MikroTik router ftpd	4.9	54	0.014
ssh	OpenSSH	5.1p1 Debian 5	53	0.013
ftp	Quick 'n Easy ftpd		53	0.013
ftp	MikroTik router ftpd	3.22	52	0.013
ftp-proxy	AVM KEN! ftp proxy		51	0.013
mongodb	MongoDB	33	49	0.012
ftp	vsftpd	2.0.4+ (ext.3)	49	0.012
mongodb	MongoDB	37	48	0.012
ftp	Serv-U ftpd	10.5	48	0.012
telnet	Cisco router telnetd		47	0.012
ftp	Serv-U ftpd	8.0	47	0.012
http	Apache	2.2.15	46	0.012
ftp	Serv-U ftpd	5.0	46	0.012
ssh	OpenSSH	3.6.1p2	45	0.011
ftp	Serv-U ftpd	4.0	45	0.011
ftp	MikroTik router ftpd	4.13	45	0.011
ftp	Serv-U ftpd	5.1	42	0.011
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
ssh	OpenSSH	5.5	40	0.01
http	Apache	2.2.22	40	0.01
ftp	ProFTPD	1.3.3f	40	0.01
ftp	bftpd	2.2.1	40	0.01
http	uTorrent WebUI		39	0.01
http	Cross Web Server		39	0.01
ssh	OpenSSH	5.3p1 Debian 3ubuntu7	38	0.01
http	nginx	1.0.11	38	0.01
ftp	WinFtpd		37	0.009
ftp	MikroTik router ftpd	2.9.2	36	0.009
http	mini_httpd	1.19 19dec2003	35	0.009
ftp	Serv-U ftpd	11.1	35	0.009
telnet	KRASNET!		34	0.009
ssh	Dropbear sshd	0.52	34	0.009
http	Boa httpd		34	0.009
ftp	MikroTik router ftpd	3.24	34	0.009
ssh	OpenSSH	5.5p1 Debian 6+squeeze2	33	0.008
ssh	OpenSSH	5.5p1 Debian 6+squeeze1	33	0.008
http	dcs-lig-httpd		33	0.008
ftp	MikroTik router ftpd	3.13	33	0.008
ftp	MikroTik router ftpd	3.11	33	0.008
http	GoAhead-Webs		32	0.008
ftp	vsftpd		32	0.008
ftp	Serv-U ftpd	7.3	32	0.008
ftp	Serv-U ftpd	11.2	32	0.008
ssl	TLS	1.0	31	0.008
ssh	OpenSSH	4.2	31	0.008
ssh	OpenSSH	5.2	30	0.008
http-proxy	Squid http proxy	2.7.STABLE9	30	0.008
http	GeoVision GeoHttpServer for webcams		30	0.008
ftp	Xlight ftpd	3.6	30	0.008
ftp	TYPSoft ftpd	1.10	30	0.008
http	uc-httpd	1.0.0	29	0.007
http	thttpd		29	0.007
http	GoAhead-Webs embedded httpd		29	0.007
ftp	WS FTPd	3.1.4	29	0.007
ftp	Serv-U ftpd	11.0	29	0.007
ftp	MikroTik router ftpd	3.10	29	0.007
ftp	IBM OS/400 FTPd		29	0.007
ssh	OpenSSH	5.8	28	0.007
nntp	INN nntpd		28	0.007
http	Hikvision-Webs		28	0.007
ftp	ProFTPD	1.2.9	28	0.007
ssh	MikroTik RouterOS sshd		27	0.007
ftp	WU-FTPD	wu-2.6.2	27	0.007
ftp	Serv-U ftpd	9.3	27	0.007
ftp	MikroTik router ftpd	2.9.7	27	0.007
telnet	Linux telnetd		26	0.007
http	YAZ Z39.50 http interface	2.1.30	26	0.007
http	Microsoft IIS httpd	5.1	26	0.007
http	Boa HTTPd	0.94.13	26	0.007
http	Apache	2.2.11	26	0.007
ftp	zFTPServer		26	0.007
ftp	Xlight ftpd	3.7	26	0.007
ftp	Serv-U ftpd	10.3	26	0.007
ftp	bftpd	1.5	26	0.007
directconnect	Direct Connect P2P		26	0.007
http	Apache	2.2.16	25	0.006
ftp	Serv-U ftpd	10.4	25	0.006
ftp	pyftpdlib	0.5.2	25	0.006
ssh	OpenSSH	5.9p1 Debian 5ubuntu1	24	0.006
http	Apache	2.2.17	24	0.006
ftp	ProFTPD	1.3.3b	24	0.006
ftp	MikroTik router ftpd	4.6	24	0.006
ftp	MikroTik router ftpd	4.15	24	0.006
ftp	bftpd	1.6	24	0.006
ftp	ALFTP		24	0.006
mongodb	MongoDB	34	23	0.006
http	thttpd	2.25b	23	0.006
ftp	Serv-U ftpd	5.2	23	0.006
ftp	Serv-U ftpd	10.0	23	0.006
ftp	ProFTPD	1.3.2a	23	0.006
ftp	FileZilla ftpd	0.9.18 beta	23	0.006
http	Microsoft IIS httpd	7.0	22	0.006
ftp	vsftpd	2.0.7+ (ext.1)	22	0.006
ftp	stupid-ftpd		22	0.006
ftp	Serv-U ftpd	11.3	22	0.006
ftp	MikroTik router ftpd	3.31	22	0.006
ftp	Guild ftpd	0.999.14	22	0.006
ftp	AD Network Video Dedicated Micros DVR ftpd		22	0.006
http	Apache	2.0.53	21	0.005
ftp	WS FTPd	5.0.5	21	0.005
ftp	TYPSoft ftpd	0.99.6	21	0.005
ftp	Serv-U ftpd		21	0.005
ftp-proxy	kingate ftp proxy	1.6	21	0.005
ftp	MikroTik router ftpd	5.0	21	0.005
mongodb	MongoDB	40	20	0.005
http	thttpd	2.24 26oct2003	20	0.005
http	Microsoft IIS httpd	7.5	20	0.005
http	HttpFileServer httpd	2.3 beta	20	0.005
http	Apache	2.2.9	20	0.005
ftp	Sonic FTP Server	1.06a	20	0.005
ftp	Serv-U ftpd	12.0	20	0.005
ftp	Serv-U ftpd	10.2	20	0.005
ftp	Rumpus ftpd		20	0.005
ftp	GNU Inetutils FTPd	1.4.1	20	0.005
sftp	ProFTPD mod_sftp	0.9.8	19	0.005
mongodb	MongoDB	41	19	0.005
http	DVR Systems webcam http interface		19	0.005
http	Apache	1.3.37	19	0.005
ftp	Serv-U ftpd	7.2	19	0.005
ftp-proxy	UserGate ftpd		19	0.005
ftp	Oracle XML DB ftpd		19	0.005
ftp	MikroTik router ftpd	3.14	19	0.005
ssh	OpenSSH	5.6	18	0.005
smtp	Microsoft Exchange smtpd		18	0.005
http	D-Link DIR-300 WAP http admin		18	0.005
ftp	vsftpd	2.0.5	18	0.005
ftp	ProFTPD	1.3.0a	18	0.005
ftp	MikroTik router ftpd	3.25	18	0.005
ftp	FileZilla ftpd	0.9.22 beta	18	0.005
sftp	ProFTPD mod_sftp	0.9.7	17	0.004
sftp	ProFTPD mod_sftp	0.9.6	17	0.004
http	Mbedthis-Appweb	2.0.4	17	0.004
http	Apache	2.2.21	17	0.004
ftp	zFTPServer	4.0 build 2010-11-26	17	0.004
ftp	Xlight ftpd	2.0	17	0.004
ftp	TYPSoft ftpd		17	0.004
ftp	MikroTik router ftpd	3.29	17	0.004
ftp	Gene6 ftpd	3.10.0 build 15	17	0.004
ftp	FileZilla ftpd	0.9.30 beta	17	0.004
upnp	Portable SDK for UPnP devices	1.3.1	16	0.004
ssh	OpenSSH	5.4p1	16	0.004
ssh	OpenSSH	2.3.0 mikrotik 2.9	16	0.004
http	uhttpd	1.0.0	16	0.004
http	Rhinosoft Serv-U httpd	10.0.0.7	16	0.004
http-proxy	Squid http proxy	2.6.STABLE12	16	0.004
http	lighttpd	1.4.20	16	0.004
http	Intoto httpd	1.0	16	0.004
http	Apache	1.3.28	16	0.004
ftp	Serv-U ftpd	7.4	16	0.004
ftp	Serv-U ftpd	7.1	16	0.004
vnc	RealVNC Enterprise		15	0.004
vnc			15	0.004
http-proxy	F5 BIG-IP load balancer http proxy		15	0.004
http	nginx		15	0.004
http	Gadspot/Avtech AV787 webcam http config		15	0.004
ftp	TYPSoft ftpd	1.11	15	0.004
ftp	Serv-U ftpd	9.4	15	0.004
ftp	MikroTik router ftpd	2.9.50	15	0.004
ftp	Gene6 ftpd	3.6.0 build 23	15	0.004