Overview of services running on Port 587 TCP.
~4.42 Million 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
smtp	Exim smtpd	1778270	40.26
smtp		1227238	27.785
smtp	Postfix smtpd	443543	10.042
smtp	Sendmail	313795	7.104
smtp	Symantec Enterprise Security manager smtpd	191806	4.343
smtp	IdeaSmtpServer smtpd	142739	3.232
smtp	Microsoft Exchange smtpd	75087	1.7
no match	-/-	55999	1.268
smtp	MailEnable smptd	35931	0.813
smtp	MDaemon smtpd	30927	0.7
smtp	Alt-N MDaemon mail server	22735	0.515
smtp	IMail NT-ESMTP	13877	0.314
smtp	Kerio Connect smtpd	12107	0.274
smtp	Microsoft ESMTP	11258	0.255
smtp	rblsmtpd wrapped smtpd	9612	0.218
smtp	mailfront smtpd	6550	0.148
nagios-nsca	Nagios NSCA	4891	0.111
smtp	Barracuda Networks Spam Firewall smtpd	4775	0.108
smtp	IceWarp smtpd	3990	0.09
smtp	Surgemail smtpd	3697	0.084
smtp	Citadel smtpd	2638	0.06
chat	AIM or ICQ server	2492	0.056
smtp	Communigate Pro SMTP	2151	0.049
smtp	NetBox smtpd	2041	0.046
smtp	XMail SMTP server	1578	0.036
smtp	Eudora EIMS X smtpd	1122	0.025
smtp	Merak Mail Server smtpd	1056	0.024
http	lighttpd	924	0.021
http		861	0.019
smtp	hMailServer	711	0.016
smtp	hMailServer smtpd	671	0.015
smtp	ArGoSoft Mail Server Pro	648	0.015
smtp	Microsoft Exchange 2010 smtpd	523	0.012
smtp	MailEnable Enterprise smptd	475	0.011
smtp	Cisco PIX sanitized smtpd	440	0.01
smtp	Code-Crafters Ability Mail Server smtpd	406	0.009
smtp	Kerio MailServer smtpd	399	0.009
smtp	Axigen smtpd	386	0.009
smtp	Symantec Messaging Gateway smtpd	351	0.008
smtp	Sun Java System Messaging Server smtpd	338	0.008
smtp	qpsmtpd	334	0.008
ssh	OpenSSH	332	0.008
http	Microsoft IIS httpd	297	0.007
smtp-proxy	ESET NOD32 anti-virus smtp proxy	292	0.007
smtp	Webwasher CSM Suite smtpd	262	0.006
smtp	Lotus Domino smtpd	254	0.006
http	thttpd	252	0.006
smtp	Kerio MailServer	224	0.005
smtp	MAILsweeper SMTP proxy	216	0.005
smtp	Post.Office	186	0.004
smtp	IA Mailserver smtpd	186	0.004
http	Microsoft HTTPAPI httpd	183	0.004
smtp	Sendmail Switch smtpd	164	0.004
smtp	Eudora smtpd	157	0.004
http	GoAhead-Webs httpd	153	0.003
smtp	DeskNow smtpd	150	0.003
ssh	Dropbear sshd	145	0.003
smtp	Unrecognized SMTP service	138	0.003
smtp	ALT-N SecurityGateway smtpd	113	0.003
http	Apache	110	0.002
smtp	AnNyung smtpd	108	0.002
ssh		103	0.002
http	Boa HTTPd	100	0.002
vnc	VNC	97	0.002
http	CCProxy	95	0.002
smtp	Mailtraq smtpd	91	0.002
smtp	Rockliffe MailSite	78	0.002
smtp	Mirapoint smtpd	77	0.002
pop3	MailEnable POP3 Server	77	0.002
smtp	Novell NetWare GroupWise Internet Agent smtpd	75	0.002
smtp	Novell GroupWise	75	0.002
smtp	Tobit David.fx smtpd	74	0.002
http-proxy	Squid http proxy	74	0.002
smtp	Mirapoint Messaging Server MOS smtpd	67	0.002
ssl	TLS	65	0.001
smtp	qmail smtpd	65	0.001
smtp	Messaging Architects M+ Extreme Email Engine smtpd	64	0.001
smtp	Oracle Communications Message Exchange imapd	61	0.001
telnet		59	0.001
smtp	JAMES smtpd	55	0.001
http	Apache Tomcat/Coyote JSP engine	54	0.001
arcserve	ARCserve Discovery	52	0.001
smtp	OpenSMTPD	50	0.001
smtp-proxy	Alligate smtp proxy	48	0.001
http	Hikvision-Webs	47	0.001
socks-proxy	CCProxy socks proxy	45	0.001
smtp	MailMarshal	44	0.001
imap	Microsoft Exchange 2007-2010 imapd	44	0.001
smtp	ArGoSoft Mail Server Freeware	41	0.001
smtp	IMail smtpd	39	0.001
smtp	Sun iPlanet smtpd	38	0.001
smtp	Nemesis smtpd	37	0.001
ftp	Microsoft ftpd	36	0.001
ftp	FileZilla ftpd	36	0.001
smtp	PowerMTA smtpd	35	0.001
smtp	Mail2000 smtpd	35	0.001
smtp	PMDF smtpd	34	0.001
pop3	Microsoft Exchange 2007-2010 pop3d	34	0.001
mysql	MySQL	34	0.001
smtp	Network Box smtpd	33	0.001
smtp-proxy	Scalix smtp relay	32	0.001
http	httpd	30	0.001
http	nginx	29	0.001
501		28	0.001
smtp-proxy	Symantec Brightmail smtp proxy	27	0.001
smtp	Allworx 6x VoIP phone smtpd	26	0.001
ftp	vsftpd	26	0.001
smtp	MailMax smtpd	25	0.001
smtp	Bizanga bizsmtp smtpd	24	0.001
smtp	TurboSendmail smtpd	23	0.001
http	http server 1.0	23	0.001
smtp	LAN-ACES MERCUR smtp server	22	0.0
smtp	RaidenMAILD smtpd	21	0.0
smtp	Cisco IronPort C160 firewall smtpd	21	0.0
smtp	VisNetic MailServer	20	0.0
smtp	Neon Mail Server smtpd	20	0.0
smtp	ArGoSoft Freeware smtpd	20	0.0
ftp		19	0.0
smtp-proxy	spamd smtpd	18	0.0
smtp	ArGoSoft Pro smtpd	17	0.0
pop3	Microsoft Exchange 2003 pop3d	17	0.0
502		17	0.0
vnc	RealVNC Enterprise	16	0.0
smtp	XWall smtpd	16	0.0
smtp	CommuniGate Pro mail server	16	0.0
smtp	FirstClass SMTP server	15	0.0
pop3	hMailServer pop3d	15	0.0
imap	Microsoft Exchange Server 2003 imapd	15	0.0
ftp	Pure-FTPd	15	0.0
ftp	ProFTPD	15	0.0
vnc	RealVNC Personal	14	0.0
telnet	Linux telnetd	14	0.0
smtp	ModusMail smtpd	14	0.0
500		14	0.0
http	GeoVision GeoHttpServer for webcams	13	0.0
ftp	Serv-U ftpd	13	0.0
xml		12	0.0
smtp	ZMailer smtpd	12	0.0
smtp	InterMail smtpd	12	0.0
tcpwrapped	BSD TCP Wrappers	11	0.0
directconnect	Direct Connect P2P	11	0.0
smtp	Synchronet smtpd	10	0.0
smtp	Smail-ESMTP	10	0.0
smtp	OpenBSD spamd	10	0.0