TCP/UDP port numbers list

This is a list of TCP and UDP port numbers used by protocols for the operation of network applications.
The Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP) only need one port for duplex, bidirectional traffic. They usually use port numbers that match the services of the corresponding TCP or UDP implementation, if they exist.

The Internet Assigned Numbers Authority (IANA) is responsible for maintaining the official assignments of port numbers for specific uses. However, many unofficial uses of both well-known and registered port numbers occur in practice. Similarly, many of the official assignments refer to protocols that were never or are no longer in common use. This article lists port numbers and their associated protocols that have experienced significant uptake.

Legend of TCP and UDP protocol table cells for port numbers:

Cell Description
Yes Described protocol is assigned for this port by IANA and is standardized, specified, or widely used for such.
Unofficial Described protocol is not assigned for this port by IANA but is standardized, specified, or widely used for such.
Assigned Described protocol is assigned by IANA for this port, but is not standardized, specified, or widely used for such.
No Described protocol is not assigned by IANA, standardized, specified, or widely used for the port.
Reserved Port is reserved by IANA, generally to prevent collision having its previous use removed. The port number may be available for assignment upon request to IANA.

This is a dynamic list and may never be able to satisfy particular standards for completeness. You can help by adding missing items with reliable sources.
The port numbers in the range from 0 to 1023 (0 to 210 − 1) are the well-known ports or system ports. They are used by system processes that provide widely used types of network services. On Unix-like operating systems, a process must execute with superuser privileges to be able to bind a network socket to an IP address using one of the well-known ports.

Ports list

Port TCP UDP SCTP DCCP Description
0 Reserved Reserved
0 N/A N/A N/A N/A In programming APIs (not in communication between hosts), requests a system-allocated (dynamic) port
1 Yes Assigned TCP Port Service Multiplexer (TCPMUX). Historic. Both TCP and UDP have been assigned to TCPMUX by IANA, but by design only TCP is specified.
5 Assigned Assigned Remote Job Entry was historically using socket 5 in its old socket form, while MIB PIM has identified it as TCP/5 and IANA has assigned both TCP and UDP 5 to it.
7 Yes Yes Echo Protocol
9 No Unofficial Wake-on-LAN
11 Yes Yes Active Users (systat service)
13 Yes Yes Daytime Protocol
15 Unofficial No Previously netstat service
17 Yes Yes Quote of the Day (QOTD)
18 Yes Yes Message Send Protocol
19 Yes Yes Character Generator Protocol (CHARGEN)
23 Yes Assigned Telnet protocol - unencrypted text communications
25 Yes Assigned Simple Mail Transfer Protocol (SMTP), used for email routing between mail servers. Create mail server monitor
27 Assigned Assigned nsw-fe (NSW User System FE)
28 Unofficial Palo Alto Networks' Panorama High Availability (HA) sync encrypted port
29 Assigned Assigned msg-icp (MSG ICP)
31 Assigned Assigned msg-auth (MSG Authentication)
33 Assigned Assigned dsp (Display Support Protocol)
37 Yes Yes Time Protocol
38 Assigned Assigned rap (Route Access Protocol)
39 Assigned Assigned rlp (Resource Location Protocol)
41 Assigned Assigned graphics (Graphics)
42 Assigned Yes Host Name Server Protocol
43 Yes Assigned WHOIS protocol
44 Assigned Assigned mpm-flags (MPM FLAGS Protocol)
45 Assigned Assigned mpm (Message Processing Module [recv])
46 Assigned Assigned mpm-snd (MPM [default send])
47 Reserved Reserved
48 Assigned Assigned auditd (Digital Audit Daemon)
49 Yes Yes TACACS Login Host protocol.TACACS+, still in draft which is an improved but distinct version of TACACS, only uses TCP 49.
50 Assigned Assigned re-mail-ck (Remote Mail Checking Protocol)
... ... ... ... ... In Progress....
49151 Reserved Reserved Reserved
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