Port

Definition
port

- a place (seaport or airport) where people and merchandise can enter or leave a country

- sweet dark-red dessert wine originally from Portugal

- an opening (in a wall or ship or armored vehicle) for firing through

- interface: (computer science) computer circuit consisting of the hardware and associated circuitry that links one device with another (especially a computer and a hard disk drive or other peripherals)

Ports in Networking
In an IP network, a port number is used to identify a network service, which allows one physical computer to listen to various protocols at the same time. The possible range for port numbers is 1 to 65535. This divides up into:

1-1024 well known ports

1024-49151 registered and unregistered ports

49152-65535 private (or dynamic) ports

Well Known Ports
The well known ports are ports between 0 and 1024, assigned by the IANA and on most systems can only be used by system (or root) processes or by programs executed by privileged users.

To the extent possible, these same port assignments are used with the UDP (RFC 768).

17-110
ports 17-110 (most widely known, complete list below)

qotd            17/tcp    Quote of the Day qotd            17/udp    Quote of the Day

msp             18/tcp    Message Send Protocol msp             18/udp    Message Send Protocol

chargen         19/tcp    Character Generator chargen         19/udp    Character Generator

ftp-data        20/tcp    File Transfer [Default Data] <-FTP ftp-data        20/udp    File Transfer [Default Data] <-FTP

ftp             21/tcp    File Transfer [Control] <-FTP ftp             21/udp    File Transfer [Control] <-FTP

ssh             22/tcp    SSH Remote Login Protocol <-SSH ssh             22/udp    SSH Remote Login Protocol <-SSH

telnet          23/tcp    Telnet <-Telnet telnet          23/udp    Telnet <-Telnet

24              24/tcp    any private mail system 24              24/udp    any private mail system

smtp            25/tcp    Simple Mail Transfer <-SMTP smtp            25/udp    Simple Mail Transfer <-SMTP


 * 1)                26/tcp    Unassigned
 * 2)                26/udp    Unassigned

nsw-fe          27/tcp    NSW User System FE nsw-fe           27/udp    NSW User System FE


 * 1)                28/tcp    Unassigned
 * 2)                28/udp    Unassigned

msg-icp         29/tcp    MSG ICP msg-icp         29/udp    MSG ICP


 * 1)                30/tcp    Unassigned
 * 2)                30/udp    Unassigned

msg-auth        31/tcp    MSG Authentication msg-auth        31/udp    MSG Authentication


 * 1)                32/tcp    Unassigned
 * 2)                32/udp    Unassigned

dsp             33/tcp    Display Support Protocol dsp             33/udp    Display Support Protocol


 * 1)                34/tcp    Unassigned
 * 2)                34/udp    Unassigned

35              35/tcp    any private printer server 35              35/udp    any private printer server


 * 1)                36/tcp    Unassigned
 * 2)                36/udp    Unassigned

time            37/tcp    Time time            37/udp    Time

rap             38/tcp    Route Access Protocol rap             38/udp    Route Access Protocol

rlp             39/tcp    Resource Location Protocol rlp             39/udp    Resource Location Protocol


 * 1)                40/tcp    Unassigned
 * 2)                40/udp    Unassigned

graphics        41/tcp    Graphics graphics        41/udp    Graphics

name            42/tcp    Host Name Server name            42/udp    Host Name Server nameserver      42/tcp    Host Name Server nameserver      42/udp    Host Name Server

nicname         43/tcp    Who Is nicname          43/udp    Who Is

mpm-flags       44/tcp    MPM FLAGS Protocol mpm-flags       44/udp    MPM FLAGS Protocol

mpm             45/tcp    Message Processing Module [recv] mpm             45/udp    Message Processing Module [recv]

mpm-snd         46/tcp    MPM [default send] mpm-snd         46/udp    MPM [default send]

ni-ftp          47/tcp    NI FTP ni-ftp          47/udp    NI FTP

auditd          48/tcp    Digital Audit Daemon auditd          48/udp    Digital Audit Daemon

tacacs          49/tcp    Login Host Protocol (TACACS) tacacs          49/udp    Login Host Protocol (TACACS)

re-mail-ck      50/tcp    Remote Mail Checking Protocol re-mail-ck      50/udp    Remote Mail Checking Protocol

la-maint        51/tcp    IMP Logical Address Maintenance la-maint        51/udp    IMP Logical Address Maintenance

xns-time        52/tcp    XNS Time Protocol xns-time        52/udp    XNS Time Protocol

domain          53/tcp    Domain Name Server domain          53/udp    Domain Name Server

xns-ch          54/tcp    XNS Clearinghouse xns-ch          54/udp    XNS Clearinghouse

isi-gl          55/tcp    ISI Graphics Language isi-gl          55/udp    ISI Graphics Language

xns-auth        56/tcp    XNS Authentication xns-auth        56/udp    XNS Authentication

57              57/tcp    any private terminal access 57              57/udp    any private terminal access

xns-mail        58/tcp    XNS Mail xns-mail        58/udp    XNS Mail

59              59/tcp    any private file service 59              59/udp    any private file service 60              60/tcp    Unassigned 60              60/udp    Unassigned

ni-mail         61/tcp    NI MAIL ni-mail         61/udp    NI MAIL

acas            62/tcp    ACA Services acas            62/udp    ACA Services

whois++         63/tcp    whois++ whois++         63/udp    whois++

covia           64/tcp    Communications Integrator (CI) covia           64/udp    Communications Integrator (CI)

tacacs-ds       65/tcp    TACACS-Database Service tacacs-ds       65/udp    TACACS-Database Service

sql*net         66/tcp    Oracle SQL*NET sql*net         66/udp    Oracle SQL*NET

bootps          67/tcp    Bootstrap Protocol Server bootps          67/udp    Bootstrap Protocol Server bootpc          68/tcp    Bootstrap Protocol Client bootpc          68/udp    Bootstrap Protocol Client

tftp            69/tcp    Trivial File Transfer tftp            69/udp    Trivial File Transfer

gopher          70/tcp    Gopher gopher          70/udp    Gopher

netrjs-1        71/tcp    Remote Job Service netrjs-1        71/udp    Remote Job Service netrjs-2        72/tcp    Remote Job Service netrjs-2        72/udp    Remote Job Service netrjs-3        73/tcp    Remote Job Service netrjs-3        73/udp    Remote Job Service netrjs-4        74/tcp    Remote Job Service netrjs-4        74/udp    Remote Job Service

75              75/tcp    any private dial out service 75              75/udp    any private dial out service

deos            76/tcp    Distributed External Object Store deos            76/udp    Distributed External Object Store

77              77/tcp    any private RJE service 77              77/udp    any private RJE service

vettcp          78/tcp    vettcp vettcp          78/udp    vettcp

finger          79/tcp    Finger finger          79/udp    Finger

http            80/tcp    World Wide Web HTTP <-HTTP http            80/udp    World Wide Web HTTP <-HTTP www             80/tcp    World Wide Web HTTP <-HTTP www             80/udp    World Wide Web HTTP <-HTTP www-http        80/tcp    World Wide Web HTTP <-HTTP www-http        80/udp    World Wide Web HTTP <-HTTP

hosts2-ns       81/tcp    HOSTS2 Name Server hosts2-ns       81/udp    HOSTS2 Name Server

xfer            82/tcp    XFER Utility xfer            82/udp    XFER Utility

mit-ml-dev      83/tcp    MIT ML Device mit-ml-dev      83/udp    MIT ML Device

ctf             84/tcp    Common Trace Facility ctf             84/udp    Common Trace Facility

mit-ml-dev      85/tcp    MIT ML Device mit-ml-dev      85/udp    MIT ML Device

mfcobol         86/tcp    Micro Focus Cobol mfcobol         86/udp    Micro Focus Cobol

87              87/tcp    any private terminal link 87              87/udp    any private terminal link

kerberos        88/tcp    Kerberos kerberos        88/udp    Kerberos

su-mit-tg       89/tcp    SU/MIT Telnet Gateway su-mit-tg       89/udp    SU/MIT Telnet Gateway


 * 1) PORT 90 also being used unofficially by Pointcast #########

dnsix           90/tcp    DNSIX Securit Attribute Token Map dnsix           90/udp    DNSIX Securit Attribute Token Map

mit-dov         91/tcp    MIT Dover Spooler mit-dov         91/udp    MIT Dover Spooler

npp             92/tcp    Network Printing Protocol npp             92/udp    Network Printing Protocol

dcp             93/tcp    Device Control Protocol dcp             93/udp    Device Control Protocol

objcall         94/tcp    Tivoli Object Dispatcher objcall         94/udp    Tivoli Object Dispatcher

supdup          95/tcp    SUPDUP supdup          95/udp    SUPDUP dixie           96/tcp    DIXIE Protocol Specification dixie           96/udp    DIXIE Protocol Specification

swift-rvf       97/tcp    Swift Remote Virtural File Protocol swift-rvf       97/udp    Swift Remote Virtural File Protocol

tacnews         98/tcp    TAC News tacnews         98/udp    TAC News

metagram        99/tcp    Metagram Relay metagram        99/udp    Metagram Relay

newacct        100/tcp    [unauthorized use]

hostname       101/tcp    NIC Host Name Server hostname       101/udp    NIC Host Name Server

iso-tsap       102/tcp    ISO-TSAP Class 0 iso-tsap       102/udp    ISO-TSAP Class 0

gppitnp        103/tcp    Genesis Point-to-Point Trans Net gppitnp        103/udp    Genesis Point-to-Point Trans Net

acr-nema       104/tcp    ACR-NEMA Digital Imag. & Comm. 300 acr-nema       104/udp    ACR-NEMA Digital Imag. & Comm. 300

cso            105/tcp    CCSO name server protocol cso            105/udp    CCSO name server protocol csnet-ns       105/tcp    Mailbox Name Nameserver csnet-ns       105/udp    Mailbox Name Nameserver

3com-tsmux     106/tcp    3COM-TSMUX 3com-tsmux     106/udp    3COM-TSMUX


 * 1)      106        Unauthorized use by insecure poppassd protocol

rtelnet        107/tcp    Remote Telnet Service rtelnet        107/udp    Remote Telnet Service

snagas         108/tcp    SNA Gateway Access Server snagas         108/udp    SNA Gateway Access Server

pop2           109/tcp    Post Office Protocol - Version 2 pop2           109/udp    Post Office Protocol - Version 2

pop3           110/tcp    Post Office Protocol - Version 3 <-POP3 pop3           110/udp    Post Office Protocol - Version 3 <-POP3

Common but unregistered ports
The unregistered ports are ports above 1024 (up to 65535) that may be on common use but are not registered with the IANA.

All ports
see Category:Ports and help it grow.