50 Common Ports You Should Know – GeeksforGeeks

Port number is a 16-bit numerical value that ranges from 0 to 65535. Well-known port (0-1023), registered port (1024-49151), and dynamic port is three types of port number space. (49152-65535).

These ports can be opened and used by software applications and operating system services to send and receive data over networks (LAN or WAN) that employ certain protocols (eg TCP, UDP).

For example, we use 80 for HTTP-web-based plain-text surfing and 443 for HTTPS-web-based encrypted websites in our daily work.

To conclude, a port is a logical form to identify system activities or various network services used to create local or network-based communications.

What are the functions of ports?

When interacting over the Internet, TCP and UDP protocols make connections, recompile data packages after the transfer, and then deliver them to applications on the recipient’s device. For this handover to work, the operating system must install and open the gateway for the transfer. Each door has a unique code number. After transmission, the receiving system uses the port number to determine where the data should be sent. The port numbers of the sender and receiver are always included in the data packet.

Ports are assigned sequential numbers from 0 to 65536. Some of these codes are standardized, meaning they are assigned to certain uses. Since code numbers are universally recognized and permanently assigned, these standard ports are also known as well-known ports. Registered ports are those that organizations or software developers have registered for their applications. Registration is handled by the Internet Assigned Numbers Authority (IANA). A diverse selection of dynamically assigned port numbers is also available. For example, when viewing websites, browsers use these ports. After that, the phone number is free again.

Why is it important to know these ports?

Any security researcher, bug bounty hunter, or anyone working with service configuration would benefit from this. Knowing how to do more thorough scans such as version detection or known vulnerabilities for ancient services that are still operating in the infrastructure, especially when using tools like Nmap, is handy when getting to know these protocols and services. 

The most 50 significant ports are listed here:

The following are some of the most common service names, transport protocol names, and port numbers used to differentiate between specific services that employ TCP, UDP, DCCP, and SCTP.

Port Number     Service name Transport protocolDescription7EchoTCP, UDPEcho service20FTP-data TCP, SCTPFile Transfer Protocol data transfer21FTP TCP, UDP, SCTPFile Transfer Protocol (FTP) control connection22SSH-SCPTCP, UDP, SCTP  Secure Shell, secure logins, file transfers (scp, sftp), and port forwarding23TelnetTCPTelnet protocol—unencrypted text communications25SMTPTCP Simple Mail Transfer Protocol, used for email routing between mail servers53DNSTCP, UDP Domain Name System name resolver69TFTPUDPTrivial File Transfer Protocol80HTTPTCP, UDP, SCTP

Hypertext Transfer Protocol (HTTP) uses TCP in versions 1.x and 2. 

HTTP/3 uses QUIC, a transport protocol on top of UDP

88KerberosTCP, UDPNetwork authentication system102Iso-tsapTCPISO Transport Service Access Point (TSAP) Class 0 protocol110POP3TCPPost Office Protocol, version 3 (POP3)135Microsoft EPMAPTCP, UDPMicrosoft EPMAP (End Point Mapper), also known as DCE/RPC Locator service, used to remotely manage services including DHCP server, DNS server, and WINS. Also used by DCOM137NetBIOS-nsTCP, UDP NetBIOS Name Service, used for name registration and resolution139NetBIOS-ssnTCP, UDPNetBIOS Session Service143IMAP4TCP, UDP Internet Message Access Protocol (IMAP), management of electronic mail messages on a server381HP OpenviewTCP, UDPHP data alarm manager383HP OpenviewTCP, UDPHP data alarm manager443HTTP over SSLTCP, UDP, SCTPHypertext Transfer Protocol Secure (HTTPS) uses TCP in versions 1.x and 2. HTTP/3 uses QUIC, a transport protocol on top of UDP.464KerberosTCP, UDPKerberos Change/Set password465SMTP over TLS/SSL, SSMTCPAuthenticated SMTP over TLS/SSL (SMTPS), URL Rendezvous Directory for SSM (Cisco protocol)587SMTPTCPEmail message submission593Microsoft DCOMTCP, UDPHTTP RPC Ep Map, Remote procedure call over Hypertext Transfer Protocol, often used by Distributed Component Object Model services and Microsoft Exchange Server636LDAP over TLS/SSLTCP, UDPLightweight Directory Access Protocol over TLS/SSL691MS ExchangeTCPMS Exchange Routing902VMware ServerunofficialVMware ESXi989FTP over SSLTCP, UDPFTPS Protocol (data), FTP over TLS/SSL990FTP over SSLTCP, UDP FTPS Protocol (control), FTP over TLS/SSL993IMAP4 over SSLTCPInternet Message Access Protocol over TLS/SSL (IMAPS)995POP3 over SSLTCP, UDPPost Office Protocol 3 over TLS/SSL1025Microsoft RPCTCPMicrosoft operating systems tend to allocate one or more unsuspected, publicly exposed services (probably DCOM, but who knows) among the first handful of ports immediately above the end of the service port range (1024+).1194OpenVPNTCP, UDPOpenVPN1337WASTEunofficialWASTE Encrypted File Sharing Program1589Cisco VQPTCP, UDPCisco VLAN Query Protocol (VQP)1725SteamUDPValve Steam Client uses port 1725 2082cPanelunofficialcPanel default2083radsec, cPanelTCP, UDP Secure RADIUS Service (radsec), cPanel default SSL2483Oracle DBTCP, UDPOracle database listening for insecure client connections to the listener, replaces port 15212484Oracle DBTCP, UDPOracle database listening for SSL client connections to the listener2967Symantec AVTCP, UDPSymantec System Center agent (SSC-AGENT)3074XBOX LiveTCP, UDPXbox LIVE and Games for Windows – Live3306MySQLTCP MySQL database system3724World of WarcraftTCP, UDPSome Blizzard games, Unofficial Club Penguin Disney online game for kids4664Google DesktopunofficialGoogle Desktop Search5432PostgreSQLTCPPostgreSQL database system5900RFB/VNC ServerTCP, UDPvirtual Network Computing (VNC) Remote Frame Buffer RFB protocol6665IRCTCPInternet Relay Chat 6669IRCTCPInternet Relay Chat 6881BitTorrentunofficialBitTorrent is part of the full range of ports used most often6999BitTorrentunofficialBitTorrent is part of the full range of ports used most often6970QuicktimeunofficialQuickTime Streaming Server8086Kaspersky AVTCPKaspersky AV Control Center8087Kaspersky AVUDPKaspersky AV Control Center8222VMware ServerTCP, UDPVMware Server Management User Interface (insecure Web interface).9100PDLTCPPDL Data Stream, used for printing to certain network printers[110000BackupExecunofficialWebmin, Web-based Unix/Linux system administration tool (default port)12345NetBusunofficialNetBus remote administration tool (often Trojan horse).27374Sub7unofficialSub7 default18006Back OrificeunofficialBack Orifice 2000 remote administration tools

My Personal Notes

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