List of Commonly Used Well Known Ports

Well Known Ports Tech Hyme

Well Known ports (also known as system ports) are numbered from 0 through 1023. In computer networking, the term port can refer to either physical or virtual connection points.

Physical network ports allow connecting cables to computers, routers, modems and other peripheral devices. Several different types of physical ports available on computer network hardware include:

  • Ethernet ports
  • USB ports
  • Serial ports

Virtual ports are part of TCP/IP networking. These ports allow software applications to share hardware resources without interfering with each other. Computers and routers automatically manage network traffic traveling via their virtual ports. Network firewalls additionally provide some control over the flow of traffic on each virtual port for security purposes.

Port number is part of the addressing information used to identify the senders and receivers of messages. Port
numbers are most commonly used with TCP/IP connections. Home network routers and computer software work with ports and sometimes allow you to configure port number settings. These port numbers allow different applications on the same computer to share network resources simultaneously.

How Port Numbers Work

Port numbers are associated with network addresses. For example, in TCP/IP networking, both TCP and UDP utilize their own set of ports that work together with IP addresses.

network well known ports

Port numbers work like telephone extensions. Just as a business telephone switchboard can use a main phone number and assign each employee an extension number (like x100, x101, etc.), so a computer has a main address and a set of port numbers to handle incoming and outgoing connections.

In both TCP and UDP, port numbers start at 0 and go up to 65535. Numbers in the lower ranges are dedicated to common Internet Protocols (like 21 for FTP, 80 for HTTP, etc.).

The port numbers from 1024 to 49151 are called registered ports. Unlike well-known ports, anyone can use these port numbers for their servers or any other use.

  • 0-1023 Well-known Ports
  • 1024-49151 Registered Ports
  • 49152-65535 Dynamic of Private Ports

A two computers began to communicate, they store the information about the session – the endpoints – so that they know where to send and receive data. For this you can use Netstat utility with command “netstat -n” where you will see many more than just two connections.

List of Commonly used Well Known Ports are:

Port # / Layer Name Comment
1 tcpmux TCP port service multiplexer
5 rje Remote Job Entry
7 echo Echo service
9 discard Null service for connection testing
11 systat System Status service for listing connected ports
13 daytime Sends date and time to requesting host
17 qotd Sends quote of the day to connected host
18 msp Message Send Protocol
19 chargen Character Generation service; sends endless stream of characters
20 ftp-data FTP data port
21 ftp File Transfer Protocol (FTP) port; sometimes used by File
Service Protocol (FSP)
22 ssh Secure Shell (SSH) service
23 telnet The Telnet service
25 smtp Simple Mail Transfer Protocol (SMTP)
37 time Time Protocol
39 rlp Resource Location Protocol
42 nameserver Internet Name Service
43 nicname WHOIS directory service
49 tacacs Terminal Access Controller Access Control System for TCP/IP
based authentication and access
50 re-mail-ck Remote Mail Checking Protocol
53 domain domain name services (such as BIND)
63 whois++ WHOIS++, extended WHOIS services
67 bootps Bootstrap Protocol (BOOTP) services; also used by Dynamic
Host Configuration Protocol (DHCP) services
68 bootpc Bootstrap (BOOTP) client; also used by Dynamic Host Control
Protocol (DHCP) clients
69 tftp Trivial File Transfer Protocol (TFTP)
70 gopher Gopher Internet document search and retrieval
71 netrjs-1 Remote Job Service
72 netrjs-2 Remote Job Service
73 netrjs-3 Remote Job Service
73 netrjs-4 Remote Job Service
79 finger Finger service for user contact information
80 http HyperText Transfer Protocol (HTTP) for World Wide Web (WWW) services
88 kerberos Kerberos network authentication system
95 supdup Telnet protocol extension
101 hostname Hostname services on SRI-NIC machines
102/tcp iso-tsap ISO Development Environment (ISODE) network applications
105 csnet-ns Mailbox nameserver; also used by CSO nameserver
107 rtelnet Remote Telnet
109 pop2 Post Office Protocol version 2
110 pop3 Post Office Protocol version 3
111 sunrpc Remote Procedure Call (RPC) Protocol for remote command
execution, used by Network Filesystem (NFS)
113 auth Authentication and Ident protocols
115 sftp Secure File Transfer Protocol (SFTP) services
117 uucp-path Unix-to-Unix Copy Protocol (UUCP) Path services
119 nntp Network News Transfer Protocol (NNTP) for the USENET
discussion system
123 ntp Network Time Protocol (NTP)
137 netbios-ns NETBIOS Name Service used in Red Hat Enterprise Linux by Samba
138 netbios-dgm NETBIOS Datagram Service used in Red Hat Enterprise Linux by Samba
139 netbios-ssn NETBIOS Session Service used in Red Hat Enterprise Linux by Samba
143 imap Internet Message Access Protocol (IMAP)
161 snmp Simple Network Management Protocol (SNMP)
162 snmptrap Traps for SNMP
163 cmip-man Common Management Information Protocol (CMIP)
164 cmip-agent Common Management Information Protocol (CMIP)
174 mailq MAILQ email transport queue
177 xdmcp X Display Manager Control Protocol (XDMCP)
178 nextstep NeXTStep window server
179 bgp Border Gateway Protocol
191 prospero Prospero distributed filesystem services
194 irc Internet Relay Chat (IRC)
199 smux SNMP UNIX Multiplexer
201 at-rtmp AppleTalk routing
202 at-nbp AppleTalk name binding
204 at-echo AppleTalk echo
206 at-zis AppleTalk zone information
209 qmtp Quick Mail Transfer Protocol (QMTP)
210 z39.50 NISO Z39.50 database
213 ipx Internetwork Packet Exchange (IPX), a datagram protocol commonly
used in Novell Netware environments
220 imap3 Internet Message Access Protocol version 3
245 link LINK / 3-DNS iQuery service
347 fatserv FATMEN file and tape management server
363 rsvp_tunnel RSVP Tunnel
369 rpc2portmap Coda file system portmapper
370 codaauth2 Coda file system authentication services
372 ulistproc UNIX LISTSERV
389 ldap Lightweight Directory Access Protocol (LDAP)
427 svrloc Service Location Protocol (SLP)
434 mobileip-agent Mobile Internet Protocol (IP) agent
435 mobilip-mn Mobile Internet Protocol (IP) manager
443 https Secure Hypertext Transfer Protocol (HTTP)
444 snpp Simple Network Paging Protocol
445 microsoft-ds Server Message Block (SMB) over TCP/IP
464 kpasswd Kerberos password and key changing services
468 photuris Photuris session key management protocol
487 saft Simple Asynchronous File Transfer (SAFT) protocol
488 gss-http Generic Security Services (GSS) for HTTP
496 pim-rp-disc Rendezvous Point Discovery (RP-DISC) for Protocol Independent
Multicast (PIM) services
500 isakmp Internet Security Association and Key Management Protocol (ISAKMP)
535 iiop Internet Inter-Orb Protocol (IIOP)
538 gdomap GNUstep Distributed Objects Mapper (GDOMAP)
546 dhcpv6-client Dynamic Host Configuration Protocol (DHCP) version 6 client
547 dhcpv6-server Dynamic Host Configuration Protocol (DHCP) version 6 Service
554 rtsp Real Time Stream Control Protocol (RTSP)
563 nntps Network News Transport Protocol over Secure Sockets Layer (NNTPS)
565 whoami whoami user ID listing
587 submission Mail Message Submission Agent (MSA)
610 npmp-local Network Peripheral Management Protocol (NPMP) local /
Distributed Queueing System (DQS)
611 npmp-gui Network Peripheral Management Protocol (NPMP) GUI /
Distributed Queueing System (DQS)
612 hmmp-ind HyperMedia Management Protocol (HMMP) Indication / DQS
631 ipp Internet Printing Protocol (IPP)
636 ldaps Lightweight Directory Access Protocol over Secure Sockets
Layer (LDAPS)
674 acap Application Configuration Access Protocol (ACAP)
694 ha-cluster Heartbeat services for High-Availability Clusters
749 kerberos-adm Kerberos version 5 (v5) ‘kadmin’ database administration
750 kerberos-iv Kerberos version 4 (v4) services
765 webster Network Dictionary
767 phonebook Network Phonebook
873 rsync rsync file transfer services
992 telnets Telnet over Secure Sockets Layer (TelnetS)
993 imaps Internet Message Access Protocol over Secure Sockets Layer (IMAPS)
994 ircs Internet Relay Chat over Secure Sockets Layer (IRCS)
995 pop3s Post Office Protocol version 3 over Secure Sockets Layer (POP3S)
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