PORT44 records
TCP & UDP Port Reference
Reference records for common TCP and UDP ports: what each port is for, which transport it uses, whether traffic is encrypted, how to check it and what to consider before opening it.
Ports are 16-bit numbers (0–65535) that let one IP address host many services at once. A TCP or UDP packet carries a destination port so the receiving system knows which program should handle it. IANA maintains the registry that maps well-known numbers to services; the records below cover the ports that people most often need to look up, check or open.
Port ranges. 0–1023 are system or well-known ports, 1024–49151 are registered ports and 49152–65535 are dynamic or ephemeral ports used for the client side of connections. See ephemeral ports and well-known port ranges.
Look up any port. For numbers not listed here, the Port Lookup tool searches the full IANA registry in your browser.
Web & HTTP
Ports that carry HTTP and HTTPS traffic for browsers, APIs, proxies and development servers.
- 80HTTPPort 80 is the default TCP port for HTTP, the unencrypted web protocol. Modern websites usually keep port 80…
- 443HTTPSPort 443 is the standard TCP port for HTTPS, the encrypted form of HTTP. Web browsers connect to it whenever…
- 3000Node.js, React & Grafana defaultPort 3000 is the conventional default for Node.js web frameworks and tools such as Express examples, Create…
- 8000Development HTTP serversPort 8000 is a common default for local development web servers, including Python's http.server, Django's…
- 8080HTTP alternatePort 8080 is the IANA-registered alternative to port 80 (http-alt). It is widely used by HTTP proxies, Java…
- 8443HTTPS alternatePort 8443 is the conventional alternative port for HTTPS, used when 443 is unavailable or reserved. It is…
Remote access & administration
Shell, desktop and management protocols. Every port in this group deserves a firewall rule.
- 22SSHPort 22 is the standard TCP port for SSH (Secure Shell), the encrypted protocol used for remote command-line…
- 23TelnetPort 23 is the TCP port for Telnet, a remote terminal protocol from 1983 that sends everything, including…
- 135RPC Endpoint Mapper (DCOM)Port 135 is the Microsoft RPC Endpoint Mapper (epmap). A client asks it which dynamic port a given RPC…
- 3389RDP (Remote Desktop)Port 3389 is the default port for Remote Desktop Protocol (RDP), which gives a full graphical Windows…
- 5900VNC (RFB)Port 5900 is the base TCP port for VNC, the Remote Framebuffer (RFB) protocol used by RealVNC, TightVNC,…
- 5985 / 5986WinRM (Windows Remote Management)Port 5985 is the HTTP listener and 5986 the HTTPS listener for Windows Remote Management (WinRM), the…
Submission, relay and retrieval ports for SMTP, IMAP and POP3, plain and encrypted.
- 25SMTP (mail relay)Port 25 is the standard TCP port for SMTP, used for server-to-server delivery of email across the internet.…
- 110POP3Port 110 is the standard TCP port for POP3 (Post Office Protocol version 3), which downloads messages from a…
- 143IMAPPort 143 is the standard TCP port for IMAP (Internet Message Access Protocol), which lets mail clients read…
- 465SMTP over TLS (SMTPS)Port 465 is used for SMTP submission over implicit TLS: the connection is encrypted from the first byte,…
- 587SMTP submissionPort 587 is the standard TCP port for message submission: a mail client sending outgoing email to its…
- 993IMAP over TLS (IMAPS)Port 993 is the standard TCP port for IMAP over TLS (IMAPS). The connection is encrypted from the start, so…
- 995POP3 over TLS (POP3S)Port 995 is the standard TCP port for POP3 over TLS (POP3S). It provides the same download-and-delete mail…
DNS, DHCP & infrastructure
The ports a network needs before anything else works: name resolution, address assignment, time, directory, logging.
- 53DNSPort 53 is the standard port for the Domain Name System. Most lookups use UDP 53; TCP 53 is used for…
- 67 / 68DHCPDHCP uses two UDP ports: servers listen on 67 and clients listen on 68. A device without an address…
- 88KerberosPort 88 is the port for Kerberos, the ticket-based authentication protocol used by Active Directory and many…
- 123NTP (Network Time Protocol)Port 123 is the UDP port for NTP, the Network Time Protocol, which keeps computer clocks synchronised.…
- 161 / 162SNMPPort 161 is the UDP port on which SNMP agents (routers, switches, printers, servers) answer monitoring…
- 389LDAPPort 389 is the standard port for LDAP, the directory protocol behind Active Directory, OpenLDAP and most…
- 514SyslogPort 514 is the traditional port for syslog, the protocol that ships log messages from routers, firewalls,…
- 636LDAPS (LDAP over TLS)Port 636 is the standard TCP port for LDAPS: LDAP wrapped in TLS from the start of the connection. Active…
- 1812 / 1813RADIUSPort 1812 is the UDP port for RADIUS authentication and 1813 for RADIUS accounting. Wi-Fi access points…
- 1900SSDP / UPnP discoveryPort 1900 is the UDP port for the Simple Service Discovery Protocol (SSDP), the discovery layer of Universal…
- 5353mDNS (Multicast DNS)Port 5353 is the UDP port for Multicast DNS (mDNS), which lets devices on a local network find each other by…
File sharing & transfer
SMB, NetBIOS, FTP and related transfer protocols.
- 20FTP data (active mode)Port 20 is the FTP data port: in active mode the server opens a connection *from* its port 20 to a port the…
- 21FTP controlPort 21 is the TCP port for the FTP control channel, where the client logs in and sends commands. File data…
- 137–139NetBIOS over TCP/IPPorts 137, 138 and 139 carry NetBIOS over TCP/IP (NBT): UDP 137 for name resolution, UDP 138 for datagrams…
- 445SMB (file sharing)Port 445 is the TCP port for SMB (Server Message Block) directly over TCP, used for Windows file and printer…
Databases & caches
Default listening ports for common database and cache servers. None of these should face the public internet.
- 1433Microsoft SQL ServerPort 1433 is the default TCP port for the default instance of Microsoft SQL Server. Named instances use…
- 1521Oracle Database listenerPort 1521 is the conventional default port for the Oracle Database listener (TNS listener), the process that…
- 3306MySQL / MariaDBPort 3306 is the default TCP port for MySQL and MariaDB database servers. Applications, ORMs and tools such…
- 5432PostgreSQLPort 5432 is the default TCP port for PostgreSQL. Access is governed by listen_addresses in postgresql.conf…
- 6379RedisPort 6379 is the default TCP port for Redis and compatible servers such as Valkey and KeyDB. Redis ships…
- 27017MongoDBPort 27017 is the default TCP port for MongoDB. Since MongoDB 3.6 the server binds to localhost only, but…
VPN & tunnelling
Ports used by VPN protocols to establish tunnels.
Applications & games
Well-known ports for specific applications, game servers and media.
Checking whether a port is open
On Windows, netstat -ano | findstr :443 shows whether anything is listening on or connected to port 443, and the PID column identifies the process. PowerShell's Test-NetConnection host -Port 443 tests whether a remote host accepts connections. See the netstat and Test-NetConnection records.
Open port does not mean compromised
A listening port means a program has asked the operating system to accept connections there. Whether that is a problem depends on which program it is, whether it should be reachable from the network it is exposed to, and whether it is patched. Records in this reference describe the normal owner of each port and how to verify it.