Well-Known TCP & UDP Ports in Networking

Network ports are software defined number  that is associated to a network protocol that transmits or receives or transmits communication for a specific application or service. It is used by Transport Layer of IP Suite, e.g. TCP & UDP.

A port number is a 16-bit unsigned integer that ranges from 0 to 65535.
There are 3 types of network ports.

Port Range Port Types Description
0 – 1023 Well-know Ports For common TCP/IP applications (assigned and controlled)
1024 – 49151 Registered Ports Used by vendors for their application (not assigned or controlled, but can be registered)
49152 – 65535 Dynamic Ports Private and non-reserved (not assigned, controlled, or registered)

This is the list of commonly used well-known ports. This is very useful especially if configuring security-related tasks like firewall administration and building access-lists (ACL).

Port# TCP UDP Service Description
7 Yes Yes Echo Echo data back to the sender
9 Yes Yes Discard Discard data at receiver
13 Yes Yes Daytime Date and Time
19 Yes Yes Chargen Character Generator
20 Yes Yes FTP-Data FTP Data Transfer
21 Yes Yes FTP FTP Connection
22 Yes Yes SSH Secure Shell Remote Login
23 Yes No Telnet Telnet Service
25 Yes No SMTP Simple Mail Transfer Protocol
37 Yes Yes Time Machine-readable time protocol
42 Yes Yes NameServ Host Name Server
43 Yes No NicName Whois
49 Yes Yes TACACS Terminal Access Controller Access-Control System
53 Yes Yes DNS Domain Name System
67 No Yes DHCP Server Server port used to send configuration
68 No Yes DHCP Client Client port used to receive configuration
69 No Yes TFTP Trivial File Transfer Protocol
79 Yes No Finger Delivers user contact information
80 Yes No HTTP HyperText Transfer Protocol
88 Yes Yes Kerberos Network authentication system
109 Yes No POP2 Post office protocol v2 for e-mail
110 Yes No POP3 Post office protocol v3 for e-mail
111 Yes Yes SunRPC RPC protocol for NFS
115 Yes No SFTP Simple File Transfer Protocol 
119 Yes No NNTP Network News Transport Protocol
123 No Yes NTP Network Time Protocol
137 Yes Yes netbios-ns NETBIOS name service
138 Yes Yes netbios-dgm NETBIOS datagram service
139 Yes Yes netbios-ssn NETBIOS session service
143 Yes Yes IMAP Internet Message Access Protocol
161 No Yes SNMP Simple Network Management Protocol
162 Yes Yes SNMPTrap Simple Network Management Protocol Trap
177 Yes Yes XDMCP X Display Manager
179 Yes No BGP Border Gateway Protocol
194 Yes Yes IRC Internet Relay Chat
220 Yes Yes IMAP3 IMAP v3 for e-mail
389 Yes Yes LDAP Lightweight Directory Access Protocol
443 Yes No HTTPS HTTP over SSL/TLS
445 Yes No Microsoft-DS SMB over TCP/IP
514 No Yes Syslog Unix system logging service
515 Yes No Printer Line Printer Daemon protocol
520 No Yes Router RIP (Routing Information Protocol)
521 No Yes RIPNG RIP (Routing Information Protocol) for IPv6
546 Yes Yes DCHPv6-client DHCP v6 client
547 Yes Yes DCHPv6-server DHCP v6 server
563 Yes Yes NTTPS NNTP over SSL/TLS
636 Yes Yes LDAPS LDAP over SSL/TLS
694 Yes Yes HA-cluster Heartbeat service
749 Yes Yes Kerberos-adm Kerberos administration
750 No Yes Kerberos-IV Kerberos v4 services
873 Yes No Rsync Rsync File Transfer
992 Yes Yes Telnets Telnet over SSL/TLS

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