Well-Known UNIX TCP and UDP Services

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Introduction

Several UNIX TCP and UDP port numbers are allocated to well-known services such as finger, SMTP (mail) and HTTP (Web). If you connect to TCP port 13 of a UNIX machine, for example, that supports the daytime service and is not behind a firewall, then it will respond with the current time. The following table lists some of these services. Keep in mind that the complete table contains thousands of entries.

Selected UNIX TCP and UDP Services

Selected UNIX TCP and UDP Services
Port	Protocol	Service	Description
7	TCP / UDP	echo	Echo Server
9	TCP / UDP	discard	Discard Server
11	TCP	systat	Active Users
13	TCP / UDP	daytime	Daytime Server
15	TCP	netstat	Netstat Server
17	TCP	qotd	Quote of the Day
18	TCP / UDP	msp	Message Send Protocol
19	TCP / UDP	chargen	TTYTST Source Character Generator
20	TCP	ftp-data	File Transfer (Data)
21	TCP	ftp-data	File Transfer (Control)
23	TCP	telnet	Telnet Server
25	TCP	smtp	Simple Mail Transfer Protocol
37	TCP / UDP	time	Time Server
43	TCP	whois	Who Is
53	TCP / UDP	domain	Domain Name Server
70	TCP	gopher	Gopher Server
79	TCP	finger	Finger Server
80	TCP	http	World Wide Web (HTTP)
443	TCP	https	World Wide Web (SSL - HTTP)
512	TCP	exec	BSD rexed
513	TCP	login	BSD rlogin
513	UDP	who	BSD rwhod
514	TCP	shell	BSD rshd
514	UDP	syslog	BSD syslogd
515	TCP	printer	BSD lpd
531	TCP	conference	Chat
6667	TCP	irc	Internet Relay Chat