UDP and TCP ports: A list of the most important ports
TCP and UDP are used to connect two devices over the Internet or other networks. However, to give data packages an entrance to the PC or server at the other end of the connection, the “doors” have to be open. These openings into the system are called ports. For both protocols, there are some known and important ports which you need to know when developing web apps.
What do ports do?
When communicating via the Internet, the two protocols TCP and UDP establish the connection, compile data packages again after transfer, and then hand them over to the programs addressed on the recipient’s device. For this handover to work, the operating system must create entrances and open them for the transfer. Every entrance has a specific code number. After the transfer, the receiving system knows where the data has to be delivered based on the port number. The data package always includes two port numbers: the sender’s and the recipient’s.
Ports have consecutive numbers – from 0 to 65536. Some of these code numbers are standardized, which means they are assigned to specific applications. These standard ports are also called well-known ports, as the code numbers are known to all and permanently assigned. There are also registered ports, which organizations or software producers have registered for their applications. The Internet Assigned Numbers Authority (IANA) is responsible for registration. There is also a wide range of port numbers that are assigned dynamically. For example, browsers use these ports when visiting a website. The number is then free again afterwards.
Ports have consecutive numbers – from 0 to 65536. Some of these code numbers are standardized, which means they are assigned to specific applications. These standard ports are also called well-known ports, as the code numbers are known to all and permanently assigned. There are also registered ports, which organizations or software producers have registered for their applications. The Internet Assigned Numbers Authority (IANA) is responsible for registration. There is also a wide range of port numbers that are assigned dynamically. For example, browsers use these ports when visiting a website. The number is then free again afterwards.
List of the most important ports
Among the over 65,000 ports, there are few code numbers that are essential for Internet communication. We want to show you the most important well-known ports and registered ports. Some of these ports are only authorized for one of the two protocols (TCP or UDP). There are also ports that were not officially registered for the service in question, but have established themselves unofficially. Some ports have double assignments.
Well-known 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 |
Registered 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 |
Ports numbered 49152 and higher are dynamic ports. They are not assigned by IANA. Any application can use these ports locally or globally in a dynamic way. As a result, it could easily be the case that one of these ports is already occupied.