Overview of services running on Port 26 TCP.
~721 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
smtp	Exim smtpd	4.77				457596	63.451
smtp	Exim smtpd	4.76				92688	12.852
smtp	Exim smtpd	4.69				42744	5.927
smtp						27249	3.778
no match						21795	3.022
smtp	Postfix smtpd					10312	1.43
http						9241	1.281
smtp	Microsoft ESMTP	6.0.3790.4675		Windows		6305	0.874
smtp	Exim smtpd					5136	0.712
smtp	Sendmail		Not accepting mail			3755	0.521
http	SonicWALL				firewall	3627	0.503
smtp	Microsoft Exchange smtpd			Windows		2319	0.322
chat	AIM or ICQ server					2187	0.303
smtp	Exim smtpd	4.63				1507	0.209
smtp	Microsoft ESMTP	6.0.3790.3959		Windows		1119	0.155
http-proxy	Squid http proxy	2.6.STABLE13				1062	0.147
smtp	Sendmail	8.14.3/8.14.3		Unix		1060	0.147
arcserve	ARCserve Discovery					993	0.138
ssh	OpenSSH	4.3	protocol 2.0			980	0.136
smtp	MailEnable smptd	1.986--		Windows		976	0.135
smtp	Symantec Enterprise Security manager smtpd					961	0.133
ssl	SSLv3					918	0.127
smtp	Microsoft ESMTP	5.0.2195.6713		Windows		878	0.122
telnet	QDX 6000 Console Utility					714	0.099
smtp	Sendmail	8.13.8/8.13.8		Unix		684	0.095
http	AIM	1.0				618	0.086
http	Apache	2.2.8	PHP/5.2.4-2ubuntu5.19 with Suhosin-Patch			563	0.078
ftp	Microsoft ftpd			Windows		485	0.067
ssh	Dropbear sshd	0.49	protocol 2.0	Linux		478	0.066
smtp	Microsoft ESMTP	5.0.2195.7381		Windows		471	0.065
smtp	Sendmail	8.14.4/8.14.4		Unix		459	0.064
smtp	Sendmail	8.13.1/8.13.1		Unix		443	0.061
http	lighttpd	1.4.19				443	0.061
ssh	MikroTik RouterOS sshd		protocol 2.0	Linux	router	425	0.059
http	lighttpd	1.4.29				424	0.059
smtp	MailEnable smptd	0-3.63-		Windows		391	0.054
smtp	MailEnable smptd	0-3.62-		Windows		324	0.045
smtp	MailEnable smptd	4.26--		Windows		306	0.042
telnet						289	0.04
smtp	Exim smtpd	4.70				271	0.038
smtp	MailEnable smptd	0-2.53-		Windows		263	0.036
smtp	MailEnable smptd	1.983--		Windows		256	0.035
smtp	Exim smtpd	4.64				254	0.035
http	a_63					240	0.033
telnet	K80 Console Utility					231	0.032
smtp	MailEnable smptd	5.10--		Windows		218	0.03
smtp	MailEnable smptd	0-5.51-		Windows		207	0.029
ssh	OpenSSH	4.2p1	protocol 2.0			192	0.027
smtp	Axigen smtpd			Unix		192	0.027
smtp	rblsmtpd wrapped smtpd		Connecting from banned IP			186	0.026
smtp	Microsoft ESMTP	6.0.3790.1830		Windows		185	0.026
ssh	OpenSSH	5.5p1 Debian 6	protocol 2.0	Linux		182	0.025
ssh	OpenSSH	4.2	protocol 2.0			178	0.025
ssh	OpenSSH	2.3.0 mikrotik 2.9	protocol 1.99		router	175	0.024
smtp	Exim smtpd	4.67				169	0.023
smtp	MailEnable smptd	-3.61-		Windows		159	0.022
smtp	Exim smtpd	4.72				158	0.022
smtp	MailEnable smptd	5.11--		Windows		157	0.022
ssh	OpenSSH	5.1p1 Debian 5	protocol 2.0	Linux		155	0.021
http	Microsoft IIS httpd	6.0		Windows		150	0.021
http	Apache	2.2.8	(Ubuntu) PHP/5.2.4-2ubuntu5.19 with Suhosin-Patch			150	0.021
ftp						146	0.02
smtp	Exim smtpd	4.71				136	0.019
smtp	Microsoft Exchange smtpd		disabled	Windows		134	0.019
telnet	Draytek Vigor ADSL router telnetd				broadband router	133	0.018
http-proxy	Squid http proxy	3.0.PRE6+PatchSets-20070623				132	0.018
ssh	OpenSSH	5.8p1-hpn13v10	protocol 2.0			131	0.018
smtp	MailEnable smptd	1.981--		Windows		126	0.017
smtp	Exim smtpd	4.68				125	0.017
ssh	OpenSSH	4.2p1	FreeBSD 20050903; protocol 2.0	FreeBSD		119	0.017
ssh	OpenSSH	5.3	protocol 2.0			116	0.016
smtp	Microsoft Exchange 2010 smtpd		not available			109	0.015
http	Microsoft HTTPAPI httpd	2.0	SSDP/UPnP	Windows		107	0.015
http	Netwave IP camera http config				webcam	104	0.014
http	GoAhead-Webs httpd					104	0.014
ssh	OpenSSH	5.4p1	FreeBSD 20100308; protocol 2.0	FreeBSD		102	0.014
smtp	Sendmail	8.14.3/8.14.3/Debian-5+lenny1		Unix		102	0.014
smtp	Barracuda Networks Spam Firewall smtpd					101	0.014
smtp	Exim smtpd	4.50				98	0.014
telnet	Intel telnetd		on Express 510T Switch			97	0.013
ssh	OpenSSH	5.3p1 Debian 3ubuntu7	Ubuntu Linux; protocol 2.0	Linux		94	0.013
ssh			protocol 1.5			93	0.013
ssh	OpenSSH	5.2	protocol 2.0			93	0.013
smtp	Microsoft ESMTP	7.5.7601.17514		Windows		93	0.013
smtp	Exim smtpd	4.75				93	0.013
ssh	Dropbear sshd	0.52	protocol 2.0	Linux		91	0.013
ssh	OpenSSH	4.5p1	FreeBSD 20061110; protocol 2.0	FreeBSD		90	0.012
telnet	Linux telnetd			Linux		88	0.012
ssh	OpenSSH	5.5p1 Debian 6+squeeze2	protocol 2.0	Linux		84	0.012
smtp	IMail NT-ESMTP	11.03 1-1		Windows		84	0.012
smtp	Alt-N MDaemon mail server	11.0.3		Windows		82	0.011
smtp	MailEnable smptd	0-3.6-		Windows		81	0.011
smtp	MailEnable smptd	3.62--		Windows		80	0.011
smtp	Exim smtpd	3.36				80	0.011
smtp	MailEnable smptd	5.51--5.51		Windows		79	0.011
http	Apache Tomcat/Coyote JSP engine	1.1				78	0.011
smtp	MailEnable smptd	4.23--		Windows		77	0.011
ssh	OpenSSH	5.1p1	FreeBSD 20080901; protocol 2.0	FreeBSD		76	0.011
http	Microsoft IIS httpd					74	0.01
smtp	MailEnable smptd	0-3.14-		Windows		73	0.01
smtp	IMail NT-ESMTP	11.03 2-1		Windows		73	0.01
smtp	Rockliffe MailSite	9.5.4.3				71	0.01
smtp	MailEnable smptd	0-6.02-		Windows		70	0.01
smtp	Allworx 6x VoIP phone smtpd				VoIP phone	69	0.01
ftp	Serv-U ftpd	6.4		Windows		68	0.009
telnet	Intel telnetd		on Intel Express 8100 Router FR			67	0.009
ssh	SCS sshd	3.2.9.1	protocol 2.0			64	0.009
smtp	Microsoft ESMTP	7.0.6002.18264		Windows		64	0.009
ssh	OpenSSH	5.5p1 Debian 6+squeeze1	protocol 2.0	Linux		63	0.009
ssh	OpenSSH	5.1	protocol 2.0			63	0.009
http	Avtech AVN801 network camera	1.0	UPnP 1.0		webcam	63	0.009
ftp	vsftpd	2.0.8 or later				63	0.009
smtp	MailEnable smptd	6.0--		Windows		61	0.008
ssh	OpenSSH	5.8	protocol 2.0			59	0.008
ssh			protocol 2.0			57	0.008
ssh	OpenSSH	5.6	protocol 2.0			55	0.008
smtp	MailEnable smptd	6.01--		Windows		55	0.008
smtp	Sendmail	8.14.2/8.14.2		Unix		54	0.007
http-proxy	Squid http proxy	2.6.STABLE12				52	0.007
http	Hikvision-Webs					52	0.007
ssh	Dropbear sshd	0.51	protocol 2.0	Linux		51	0.007
smtp	Sendmail	8.14.3/8.14.3/Debian-9.4		Unix		51	0.007
smtp	Exim smtpd	4.73				51	0.007
ssh	OpenSSH	4.4	protocol 2.0			49	0.007
pop3	hMailServer pop3d			Windows		49	0.007
smtp	MailEnable smptd	6.5--6.5		Windows		48	0.007
smtp	MailEnable smptd	6.53--		Windows		48	0.007
smtp	MailEnable smptd	6.03--		Windows		47	0.007
ssh	OpenSSH	5.4	protocol 2.0			45	0.006
ssh	OpenSSH	5.9p1 Debian 5ubuntu1	Ubuntu Linux; protocol 2.0	Linux		44	0.006
ssh	OpenSSH	5.5	protocol 2.0			43	0.006
smtp	Cisco PIX sanitized smtpd				firewall	42	0.006
http	PDR-M800	1.0				42	0.006
smtp	Sendmail	8.12.11.20060308/8.12.11		Unix		41	0.006
smtp	Merak Mail Server smtpd	8.0.3		Windows		41	0.006
smtp	MailEnable smptd	4.22--		Windows		41	0.006
smtp	IceWarp smtpd	9.3.2				41	0.006
http	Apache					41	0.006
smtp	Sendmail	8.12.8/8.12.8		Unix		40	0.006
ftp	Serv-U ftpd	6.3		Windows		40	0.006
ssh	OpenSSH	3.9p1	protocol 1.99			39	0.005
smtp	MailEnable smptd	5.51--		Windows		39	0.005
vnc	VNC		protocol 3.8			38	0.005
smtp	MailEnable smptd	0-3.61-		Windows		38	0.005
ssh	Dropbear sshd	0.53.1	protocol 2.0	Linux		37	0.005
smtp	MailEnable smptd	5.03--		Windows		37	0.005
smtp	MailEnable smptd	--3.63		Windows		37	0.005
smtp	MailEnable smptd	0-6.53-		Windows		37	0.005
smtp	MailEnable Enterprise smptd	3.10		Windows		37	0.005
http	CCProxy					36	0.005
smtp	Sendmail	8.14.3/8.13.4		Unix		35	0.005
smtp	Alt-N MDaemon mail server	12.5.6		Windows		35	0.005
ssh	OpenSSH	5.8p1 Debian 7ubuntu1	Ubuntu Linux; protocol 2.0	Linux		34	0.005
smtp	RaidenMAILD smtpd	1916		Windows		34	0.005
smtp-proxy	ESET NOD32 anti-virus smtp proxy					34	0.005
smtp	MailEnable smptd	0-2.37-		Windows		34	0.005
smtp	Kerio Connect smtpd	7.4.0				34	0.005
smtp	Alt-N MDaemon mail server	10.0.0		Windows		34	0.005
smtp	Microsoft ESMTP	7.0.6002.18222		Windows		33	0.005
smtp	Surgemail smtpd	6.0a5-5				32	0.004
smtp	MailEnable smptd	0-5.10-		Windows		32	0.004
napster	WinMX or Lopster Napster P2P client					32	0.004
http	Boa HTTPd	0.94.13				32	0.004
ftp	Pure-FTPd					32	0.004
smtp	MailEnable smptd	6.5--		Windows		31	0.004
smtp	Sendmail	8.14.3/8.14.2		Unix		29	0.004
smtp	Postfix smtpd		ispCP OMEGA 1.0.7			29	0.004
smtp	MailEnable smptd	1.9--	Denied access	Windows		29	0.004
http	mini_httpd	1.19 19dec2003				29	0.004
ssh	OpenSSH	5.8p1 Debian 1ubuntu3	Ubuntu Linux; protocol 2.0	Linux		28	0.004
ssh	OpenSSH	5.4p1_hpn13v11	FreeBSD 20100308; protocol 2.0	FreeBSD		28	0.004
ssh	OpenSSH	4.3p2 Debian 9etch3	protocol 2.0	Linux		28	0.004
smtp-proxy	UserGate smtp proxy			Windows		28	0.004
smtp	MailEnable smptd	0-4.22-		Windows		28	0.004
smtp	MailEnable smptd	0-1.87-		Windows		28	0.004
telnet	Intel telnetd		on Express 550T Switch			27	0.004
ssl	Microsoft IIS SSL			Windows		27	0.004
smtp	Sendmail	8.13.8/8.13.1		Unix		27	0.004
smtp	Postfix smtpd		ispCP OMEGA 1.0.5			27	0.004
smtp	MailEnable smptd	-4.26-		Windows		27	0.004
smtp	MailEnable smptd	4.17--		Windows		27	0.004
ssh	OpenSSH	3.6.1p2	protocol 1.99			26	0.004
smtp	MDaemon smtpd	9.5.2	Unregistered	Windows		26	0.004
http-proxy	Squid http proxy	2.7.STABLE9				26	0.004
ftp	Microsoft ftpd	5.0		Windows		26	0.004
smtp	Sendmail	8.14.5/8.14.5		Unix		25	0.003
smtp	MailEnable smptd	0-4.26-		Windows		25	0.003
smtp	Alt-N MDaemon mail server	11.0.0		Windows		25	0.003
smtp	Microsoft ESMTP	7.5.7600.16601		Windows		24	0.003
smtp	Alt-N MDaemon mail server	12.5.4		Windows		24	0.003
ftp	Synology DiskStation NAS ftpd				storage-misc	24	0.003
smtp	MailEnable smptd	0-6.52-		Windows		23	0.003
smtp	Exim smtpd	4.62				23	0.003
smtp	Communigate Pro SMTP	4.3.9				23	0.003
smtp	Alt-N MDaemon mail server	10.1.0		Windows		23	0.003
http	GoAhead-Webs					23	0.003
http	Boa HTTPd	0.94.14rc21				23	0.003
ssh	OpenSSH	5.8p2_hpn13v11	FreeBSD 20110503; protocol 2.0	FreeBSD		22	0.003
smtp	Symantec Messaging Gateway smtpd					22	0.003
smtp	Sendmail	8.13.4/8.13.4/Debian-3sarge3		Unix		22	0.003
smtp	Rockliffe MailSite	9.5.4.5				22	0.003
smtp	RaidenMAILD smtpd	2103		Windows		22	0.003
smtp	MailEnable smptd	4.25--		Windows		22	0.003
smtp	MailEnable smptd	-2.40-		Windows		22	0.003
smtp	MailEnable smptd	0-2.36-		Windows		22	0.003
smtp	Kerio Connect smtpd	7.3.2				22	0.003
smtp	Cisco IronPort C160 firewall smtpd			AsyncOS		22	0.003
ssh	OpenSSH	4.5	protocol 2.0			21	0.003
smtp	MailEnable smptd	4.25--4.26		Windows		21	0.003
smtp	MailEnable smptd	-2.53-		Windows		21	0.003
smtp	MailEnable smptd	0-5.53-		Windows		21	0.003
smtp	MailEnable Enterprise smptd	2.53		Windows		21	0.003
http	Apache		SSL-only mode			21	0.003
ftp	ProFTPD	1.3.1		Unix		21	0.003
ftp	FileZilla ftpd	0.9.40 beta		Windows		21	0.003
telnet	Cisco 1721 router telnetd			IOS	router	20	0.003
ssh	Dropbear sshd	0.50	protocol 2.0	Linux		20	0.003
smtp	XMail SMTP server	1.27				20	0.003
smtp	MailEnable smptd	0-6.03-		Windows		20	0.003
smtp	MailEnable smptd	0-4.11-		Windows		20	0.003
http	Mbedthis-Appweb	2.0.4				20	0.003
ftp	FileZilla ftpd	0.9.41 beta		Windows		20	0.003