Common Ports List: TCP and UDP Port Numbers

A port number tells a computer which program should receive a piece of network traffic. The IP address gets data to the right device, and the port gets it to the right service on that device, such as a web server on port 443 or SSH on port 22. The list below covers the ports you are most likely to meet, with the names they are registered under at IANA, the body that assigns them. To see whether a port is reachable on your own connection, use our port checker.

What is a port number?

A port is a number from 0 to 65535 that is part of every TCP and UDP connection. A server program listens on a fixed port so that clients know where to find it, and your device picks a temporary port for its own end of each connection. TCP and UDP each have their own set of numbers, so a service can be registered for TCP, for UDP or for both.

The three port ranges

RFC 6335 splits the 65,536 port numbers into three ranges, and IANA only hands out numbers in the first two.

Because dynamic ports are never assigned, any program can use them for short-lived connections. Most of the services people search for sit in the well-known range.

Common ports list

Each entry is the service name and protocol from the IANA registry, with a note on what you will usually find using it.

A registration only says what a port is reserved for. Any program can be set to listen on any port, so traffic on port 443 is very likely HTTPS but not guaranteed to be.

The most searched ports

Port 443

Port 443 is HTTPS, the encrypted web. HTTP's own standard, RFC 9110, makes 443 the default port for https addresses, which is why you never have to type it. It is registered for both TCP and UDP. Blocking it breaks most websites and apps.

Port 80

Port 80 is plain HTTP, the default for http addresses in RFC 9110. Many sites answer on port 80 only to send you on to the HTTPS version on 443.

Port 22

Port 22 is SSH, used to log in to servers and routers securely, copy files with SFTP or SCP, and push code to Git hosts. A server that exposes it to the internet should allow key-based logins only.

Port 53

Port 53 is DNS, registered for both UDP and TCP. Encrypted DNS over TLS has its own port, 853. Our DNS server guide explains what happens when your device asks a resolver for an address.

Port 3389

Port 3389 is Windows Remote Desktop. Microsoft's documentation confirms that Remote Desktop listens on 3389 by default and shows how to change it. CISA lists exposed RDP among the weaknesses used in ransomware attacks, where attackers log in with weak or stolen passwords, and recommends multi-factor authentication.

Port 8080

Port 8080 is registered as an alternate HTTP port. It is a common choice for a second web server on the same machine, a development server or a web proxy, since port 80 is often already taken.

Which ports are risky to open?

Every port you forward on your router lets the whole internet knock on that service. A few deserve extra care.

• Remote Desktop (3389). CISA warns that attackers break in through RDP with weak or compromised credentials. Put it behind a VPN or use multi-factor authentication.
• SMB file sharing (139 and 445). CISA notes that the old SMBv1 version sends everything in clear text, and recommends a newer SMB version and carrying SMB over an encrypted VPN.
• Databases (1433, 3306, 5432, 6379, 27017). These are meant for your own apps to reach. Keep them on the local network or behind a VPN.
• Telnet (23) and plain FTP (21). Use SSH and SFTP instead, which encrypt the session.

Our guide to port forwarding covers opening a port safely when you do need one.

TCP ports vs UDP ports

TCP sets up a connection with a handshake before any data moves, so you can test a TCP port by trying to connect. UDP just sends packets, with no handshake and no resending, which suits DNS lookups, calls and games. Because nothing answers a probe, an open UDP port is hard to confirm from outside, and that is why our port checker tests TCP.

How to check which ports are open

Use the port checker to test whether a port on your public IP address can be reached from the internet. To see what is listening on your own computer, run netstat -an on Windows or lsof -i -P on a Mac. Our guide on how to check if a port is open walks through each method and what the results mean.

Frequently asked questions

How many ports are there?

There are 65,536 port numbers, from 0 to 65535, for each of TCP and UDP. Numbers 0 to 1023 are well-known ports, 1024 to 49151 are registered ports, and 49152 to 65535 are dynamic ports that IANA never assigns.

What port does HTTPS use?

Port 443. Plain HTTP uses port 80.

What port does email use?

Mail servers talk to each other on port 25. Mail apps send through 465 (TLS from the start) or 587, and read mail through IMAP on 993 or POP3 on 995. RFC 8314 recommends the TLS-from-the-start ports over upgrading a plain connection.

Is port 8080 the same as port 80?

Both carry HTTP, but they are separate ports. A server on 8080 has to be addressed with the port in the URL, for example http://example.com:8080.

Sources and further reading

• IANA Service Name and Transport Protocol Port Number Registry
• RFC 6335: IANA procedures for port numbers, including the three ranges (IETF)
• RFC 9110: HTTP Semantics, default ports 80 and 443 (IETF)
• RFC 2131: Dynamic Host Configuration Protocol, ports 67 and 68 (IETF)
• RFC 8314: Use of TLS for email submission and access (IETF)
• Microsoft Learn: Change the Remote Desktop listening port
• CISA: Misconfigurations and weaknesses known to be used in ransomware campaigns