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Common Network Ports Reference

Searchable list of the TCP and UDP ports IT professionals meet every day — firewall rules, port scans, service troubleshooting.

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PortProtoServiceDescription

About the Port Reference

Every network service listens on a port, and most troubleshooting eventually comes down to “is that port open, and what is supposed to be on it?” This reference covers the ports IT support technicians and network administrators actually meet: web and mail protocols, Windows and Active Directory traffic, VPNs, databases, VoIP, printing, virtualisation and monitoring. Use the search box for a port number or service name, or filter by category.

Ports 0–1023 are the IANA “well-known” range, 1024–49151 are registered ports, and 49152–65535 are dynamic/ephemeral ports used for outbound connections. Remember that a port number is only a convention — nothing stops an administrator running SSH on 2222 or a web server on 8080, which is why port scans report the service actually responding, not just the number.

How to Use This Tool

1
Type a port number, protocol or service name into the search box — 3389, smtp and kerberos all work.
2
The table filters as you type across every column, so partial matches like sql surface MSSQL, MySQL and PostgreSQL together.
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Check the protocol column carefully: some services need TCP, some UDP, and some (like DNS) need both.
4
Use the description to confirm you've found the right service before writing the firewall rule or interpreting the scan result.

Common Use Cases

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    Writing firewall rules. Confirm exactly which ports and protocols a new printer, camera system or application server needs before opening anything wider than necessary.
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    Interpreting port scans. Turn a raw nmap result into meaning — 445 open on an unknown host says something very different from 8080.
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    Security reviews. Spot legacy risk quickly: telnet (23), unencrypted FTP (21) or SMBv1-era services listening where they shouldn't be.
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    Troubleshooting connectivity. When "the app doesn't work" turns out to be a blocked port, look up what the app actually uses and test that specific port.
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    Certification study. A searchable, annotated port list beats flashcards for CompTIA, CCNA and similar exams — search by service and self-test.

Quick Testing Commands

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    Windows: Test-NetConnection host -Port 443 in PowerShell checks TCP reachability.
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    Linux/macOS: nc -zv host 443 or curl -v telnet://host:443.
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    What is listening locally? netstat -ano (Windows) or ss -tlnp (Linux).
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    Firewall rules: allow the specific port and protocol, not broad ranges — and note TCP vs UDP matters.

Frequently Asked Questions

What's the difference between well-known, registered and dynamic ports?
Well-known ports (0–1023) are reserved for core services like HTTP and SSH and need elevated privileges to bind on most systems. Registered ports (1024–49151) are assigned to specific applications by IANA. Dynamic ports (49152–65535) are used for ephemeral client-side connections.
An open port showed up in a scan — is that a problem?
An open port is only a problem if the service behind it shouldn't be exposed to that network. Match the port to this table, ask whether that service belongs on that host, and whether the source networks that can reach it are the ones you intend.
What is the difference between TCP and UDP for the same port number?
TCP and UDP port spaces are independent. DNS uses UDP 53 for most queries and TCP 53 for zone transfers and large responses. A firewall rule for one does not open the other.
Which ports should never be exposed to the internet?
SMB (445), RDP (3389) without a gateway, databases (1433, 3306, 5432, 6379, 27017, 11211), Docker (2375) and WinRM are the most commonly exploited. Put them behind a VPN or zero-trust gateway.
Why does HTTPS show as UDP 443 sometimes?
HTTP/3 runs over QUIC, which uses UDP 443. Modern browsers use it automatically when the server supports it, so firewalls should treat UDP 443 as web traffic too.