Network Ports

In computer networking, there are network port numbers used for various applications. The range of these network ports are from 0 to 65535. There are three different port types used networking. These network port types are given below:

 

• Well-known Ports (0 – 1023)
• Registered Ports (1024 – 49151)
• Dynamic Ports (Private Ports) (49152 – 65565)

 

Some of these port numbers are well-known ports. These well-known ports are the reserved ports between 0 and 1023. The full list of these network port numbers are given in RFC 1700. IANA (Internet Assigned Numbers Authority) assigns these well-known ports.

 

The other network ports are registered ports between 1024 and 49151. These ports are assigned by IANA for specific services.

 

The last part of ports in networking are dynamic ports. Daynamic ports are the ports from 49152 to 65565. These ports in networking are not registered with IANA.

 

TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) uses these well-known ports. Only one port is required for full-duplex, bidirectional traffic. Beside SCTP (Stream Control Transmission Protocol) and DCCP (Datagram Congestion Control Protocol) use these ports.

 

You can download the Cheat Sheet about Well-known network ports.

 

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Well Known Ports in Networking

Well-known network ports are from 0 to 1024. These port numbers are given by IANA (Internet Assigned Numbers Authority). And the full list of these port numbers are in RFC 1700.

 

Some of these  well-known ports are used by TCP and some of them are used UDP. These TCP and UDP ports are also asked in many network engineering technical interviews as interview questions. So, what are these ports in networking?

 

Well-known TCP ports are the network ports used by the applications that works with TCP as transport protocol. So, what are these applications that uses well-known TCP ports?

 

For example, FTP (File Transport Protocol) is one of the applications that uses TCP ports. The FTP ports are TCP port 20 and TCP port 21. The other applcation that uses TCP as transport protocol is Telnet. Telnet uses TCP port 23.

 

Well-known UDP ports are the network ports used by the applications that works with UDP as transport protocol. So, what are these applications that uses well-known UDP ports?

 

For example TFTP (Trivial File Transport Protocol) is one of the applciations that uses UDP ports. UDP port 69 is used by TFTP. Another example that uses UDP as transport protocol is SNMP. SNMP uses UDP port 161 for SNMP and UDP port 162 for SNMP trap messages.

 

Below, you can find all the wellknown ports used by the applications that uses TCP & UDP network ports.

 

Port	TCP	UDP	Name	Description
1	✔	✔	tcpmux	TCP port multiplexer
5	✔	✔	rje	Remote job entry
7	✔	✔	echo	Echo service
9	✔	✔	discard	Zero service for test purposes
11	✔	✔	systat	System information
13	✔	✔	daytime	Time and date
17	✔	✔	qotd	Sends quote of the day
18	✔	✔	msp	Sends text messages
19	✔	✔	chargen	Sends an infinite character string
20	✔		ftp-data	FTP data transfer
21	✔	✔	ftp	FTP connection
22	✔	✔	ssh	Secure Shell Service
23	✔		telnet	Telnet service
25	✔		smtp	Simple Mail Transfer Protocol
37	✔	✔	time	Machine-readable time protocol
39	✔	✔	rlp	Resource location protocol
42	✔	✔	nameserver	Name service
43	✔		nicname	WHOIS directory service
49	✔	✔	tacacs	Terminal access controller access control system
50	✔	✔	re-mail-ck	Remote mail checking
53	✔	✔	domain	DNS name resolver
67		✔	bootps	Bootstrap protocol services
68		✔	bootpc	Bootstrap client
69		✔	tftp	Trivial file transfer protocol
70	✔		gopher	Document search
71	✔		genius	Genius protocol
79	✔		finger	Delivers user contact information
80	✔		http	Hypertext transfer protocol
81	✔			Torpark: Onion routing (unofficial)
82		✔		Torpark: Control (unofficial)
88	✔	✔	kerberos	Network authentication system
101	✔		hostname	NIC host name
102	✔		Iso-tsap	ISO TSAP protocol
105	✔	✔	csnet-ns	Mailbox mail server
107	✔		rtelnet	Remote telnet
109	✔		pop2	Post office protocol v2 for e-mail communication
110	✔		pop3	Post office protocol v3 for e-mail communication
111	✔	✔	sunrpc	RPC protocol for NFS
113		✔	auth	Authentication service
115	✔		sftp	Simple file transfer protocol
117	✔		uucp-path	File transfer between Unix systems
119	✔		nntp	Transfer of messages in news groups
123		✔	ntp	Time synchronization service
137	✔	✔	netbios-ns	NETBIOS name service
138	✔	✔	netbios-dgm	NETBIOS datagram service
139	✔	✔	netbios-ssn	NETBIOS session service
143	✔	✔	imap	Internet message access protocol for e-mail communication
161		✔	snmp	Simple network management protocol
162	✔	✔	snmptrap	Simple network management protocol trap
177	✔	✔	xdmcp	X display manager
179	✔		bgp	Border gateway protocol
194	✔	✔	irc	Internet relay chat
199	✔	✔	smux	SNMP UNIX multiplexer
201	✔	✔	at-rtmp	AppleTalk routing
209	✔	✔	qmtp	Quick mail transfer protocol
210	✔	✔	z39.50	Bibliographic information system
213	✔	✔	ipx	Internetwork packet exchange
220	✔	✔	imap3	IMAP v3 for e-mail communication
369	✔	✔	rpc2portmap	Coda file system port mapper
370	✔	✔	codaauth2	Coda file system authentication service
389	✔	✔	ldap	Lightweight directory access protocol
427	✔	✔	svrloc	Service location protocol
443	✔		https	HTTPS (HTTP over SSL/TLS)
444	✔	✔	snpp	Simple network paging protocol
445	✔		microsoft-ds	SMB over TCP/IP
464	✔	✔	kpasswd	Kerberos password change
500		✔	isakmp	Security protocol
512	✔		exec	Remote process execution
512		✔	comsat/biff	Mail client and server
513	✔		login	Login to remote computer
513		✔	who	Whod user logging daemon
514	✔		shell	Remote shell
514		✔	syslog	Unix system logging service
515	✔		printer	Line printer daemon print services
517		✔	talk	Talk remote calling
518		✔	ntalk	Network talk
520	✔		efs	Extended file name server
520		✔	router	Routing information protocol
521		✔	ripng	Routing information protocol for IPv6
525		✔	timed	Time server
530	✔	✔	courier	Courier remote procedure call
531	✔	✔	conference	Chat over AIM and IRC
532	✔		netnews	Netnews newsgroup service
533		✔	netwall	Emergency broadcasts
540	✔		uucp	Unix-to-Unix copy protocol
543	✔		klogin	Kerberos v5 remote login
544	✔		kshell	Kerberos v5 remote shell
546	✔	✔	dhcpv6-client	DHCP v6 client
547	✔	✔	dhcpv6-server	DHCP v6 server
548	✔		afpovertcp	Apple filing protocol over TCP
554	✔	✔	rtsp	Real time streaming protocol
556	✔		remotefs	Remote file system
563	✔	✔	nntps	NNTP over SSL/TLS
587	✔		submission	Message submission agent
631	✔	✔	ipp	Internet printing protocol
631	✔	✔		Common Unix printing system (unofficial)
636	✔	✔	ldaps	LDAP over SSL/TLS
674	✔		acap	Application configuration access protocol
694	✔	✔	ha-cluster	Heartbeat service
749	✔	✔	kerberos-adm	Kerberos v5 administration
750		✔	kerberos-iv	Kerberos v4 services
873	✔		rsync	rsync file transfer services
992	✔	✔	telnets	Telnet over SSL/TLS
993	✔		imaps	IMAP over SSL/TLS
995	✔		pop3s	POP3 over SSL/TLS

 

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Registered Network Ports

Registered networking ports start from port 1024 to 49151. IANA (Internet Assigned Numbers Authority)  assigns these registerd network ports. Below, you can find these registered networking ports

 

Port	TCP	UDP	Name	Description
1080	✔		socks	SOCKS proxy
1433	✔		ms-sql-s	Microsoft SQL server
1434	✔	✔	ms-sql-m	Microsoft SQL monitor
1494	✔		ica	Citrix ICA client
1512	✔	✔	wins	Windows internet name service
1524	✔	✔	ingreslock	Ingres DBMS
1701		✔	l2tp	Layer 2 tunneling protocol/Layer 2 forwarding
1719		✔	h323gatestat	H.323
1720	✔		h323hostcall	H.323
1812	✔	✔	radius	RADIUS authentication
1813	✔	✔	radius-acct	RADIUS access
1985		✔	hsrp	Cisco HSRP
2008	✔			Teamspeak 3 accounting (unofficial)
2010		✔		Teamspeak 3 web list (unofficial)
2049	✔	✔	nfs	Network file system
2102	✔	✔	zephyr-srv	Zephyr server
2103	✔	✔	zephyr-clt	Zephyr client
2104	✔	✔	zephyr-hm	Zephyr host manager
2401	✔		cvspserver	Concurrent versions system
2809	✔	✔	corbaloc	Common object request broker architecture
3306	✔	✔	mysql	MySQL database service (also for MariaDB)
4321	✔		rwhois	Remote whois service
5999	✔		cvsup	CVSup
6000	✔		X11	X Windows system services
11371	✔		pgpkeyserver	Public keyserver for PGP
13720	✔	✔	bprd	Symantec/Veritas NetBackup
13721	✔	✔	bpdbm	Symantec/Veritas database manager
13724	✔	✔	vnetd	Symantec/Veritas network utility
13782	✔	✔	bpcd	Symantec/Veritas NetBackup
13783	✔	✔	vopied	Symantec/Veritas VOPIE
22273	✔	✔	wnn6	Kana/Kanji conversion
23399				Skype (unofficial)
25565	✔			Minecraft
26000	✔	✔	quake	Quake and other multiplayer games
27017				MongoDB
33434	✔	✔	traceroute	Network tracking

 

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Dynamic Networking Ports

Registered networking ports are the ports from 49152 to 65565. These ports can be used locally or dynamically by the applications. They are not assigned by IANA.

 

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Network Ports Practice

Quesitons For Networking Ports

Question 1: Which network port range is reserved as Well-known Ports?

a) 0 – 1024

b) 1024 – 49151

c) 49152 – 65565

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Question 2: Which network port range is reserved as Registered Ports ?

a) 0 – 1024

b) 1024 – 49151

c) 49152 – 65565

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Question 3: Which network port range is reserved as Dynamic Ports ?

a) 0 – 1024

b) 1024 – 49151

c) 49152 – 65565

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Question 4: Network port numbers are assigned by ….

a) ITU

b) IANA

c) IETF

d) ISO

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Question 5: Which ones are the default network ports for FTP ?

a) UDP 20, 21

b) TCP 20, 21

c) UDP 22,23

d) TCP 22,23

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Question 6: Which ones are the default SNMP Ports?

a) UDP 157, 158

b) TCP 157, 158

c) UDP 161, 162

d) TCP 161, 162

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Question 7: What is the default Telnet port?

a) TCP 20

b) TCP 21

c) TCP 22

d) TCP 23

e) TCP 24

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Question 8: Which ones are the default TFTP Port?

a) UDP 69

b) TCP 69

c) UDP 58

d) TCP 58

e) UDP 45

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Question 9: TCP Port 25 is the default network port of ….

a) TFTP

b) SNMP

c) Telnet

d) SMTP

e) FTP

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Question 10: UDP Port 123 is the default network port of ….

a) HTTP

b) SFTP

c) NTP

d) TFTP

e) SMTP

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Answers: 1)a    2)b   3)c    4)b    5)b    6)c   7)d    8)a  9)d  10)c