Common TCP & UDP Ports Reference
A searchable table of the most common TCP and UDP port numbers and the services that use them. Type a port, a service name or a keyword to filter instantly — everything runs in your browser.
| Port | Protocol | Service | Description |
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Every network conversation happens over a port — a 16-bit number from 0 to 65535 that tells a machine which service a packet is meant for. An IP address gets the packet to the right host; the port gets it to the right program on that host. When your browser opens https://example.com, it connects to the server's IP on TCP port 443, and the server knows to hand that traffic to its web software.
Ports are split into three ranges by IANA. Well-known ports (0–1023) are reserved for core services like HTTP, HTTPS, SSH and DNS. Registered ports (1024–49151) are used by databases and applications such as MySQL (3306) and PostgreSQL (5432). Dynamic or ephemeral ports (49152–65535) are handed out temporarily for the client side of a connection.
Port 53 on TCP and port 53 on UDP are not the same channel — they just share a number. DNS famously uses both: UDP 53 for quick lookups and TCP 53 for larger responses and zone transfers. Always note the protocol alongside the port when writing firewall rules.
This list covers the ports you will meet most often when configuring servers, reading firewall logs or studying for a networking exam. It is not exhaustive — IANA maintains the full registry of thousands of assignments — but these are the ones worth committing to memory. Remember that a port number is only a convention: you can move SSH to 2222 or run a web server on 8080, but then clients must specify the non-default port explicitly.
Want the underlying theory? Read What is a network port? for a friendly explanation, or HTTP vs HTTPS to understand why ports 80 and 443 behave so differently. When you need to test what is actually listening, pair this reference with our DNS Lookup and IP Protocol Numbers tools.
Frequently asked questions
What is the difference between a TCP and a UDP port?
Both TCP and UDP use 16-bit port numbers (0–65535), but they are independent number spaces. TCP is connection-oriented and reliable, so it is used for the web (80/443) and SSH (22). UDP is connectionless and lightweight, so it suits DNS (53), DHCP (67/68) and real-time streaming. The same number can be assigned to different services on TCP and UDP.
What are well-known ports?
Well-known ports are 0–1023 and are assigned by IANA to widely used system services such as HTTP (80), HTTPS (443) and SMTP (25). Ports 1024–49151 are registered ports, and 49152–65535 are dynamic or ephemeral ports used for temporary client connections.
What port does HTTPS use?
HTTPS uses TCP port 443 by default, while plain HTTP uses TCP port 80. When you type a URL without a port, the browser assumes 443 for https:// and 80 for http://.
Can I change the port a service runs on?
Yes — port numbers are conventions, not hard rules. You can run SSH on 2222 or a web server on 8080, but clients then have to specify the non-standard port. Using default ports keeps configuration simple and lets firewalls and monitoring recognise the traffic.
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