Which ports does it know?

Well-known ports (0-1023) fully, registered ports (1024-49151) for common services, ephemeral range (49152+) documented but not individually listed.

Is the list IANA-official?

Yes — matches IANA's registered services. Some ports have both official and common-convention uses; both are shown.

What's the difference between TCP and UDP ports?

Separate namespaces — port 53 TCP and port 53 UDP are different things. DNS uses both. The tool shows protocol per service.

Why is port 22 always SSH?

Registered with IANA in 1995. Changing SSH's port is possible (security through obscurity) but most tools default to 22.

Port Reference Lookup | DevTools Surf

DevTools Surf

Example: Port Reference Lookup

A worked example, rendered from real sample data. Sign in to run the tool on your own input.

Input

Output

═══ Port 443/TCP/UDP — HTTPS ═══
Service name: https
Range: Well-known
Category: Web
Applications: Web server
Description: HTTP over TLS — the encrypted public web. Also QUIC/HTTP3 on UDP.
Specification: RFC 9110
Encrypted by default: yes
Common alternates: 8443, 4443, 9443

─── /etc/services line ───
  https           443/tcp

─── Exposure ───
✓ Commonly exposed.

─── Quick test ───
  nc -zv <host> 443
  nmap -sU -p 443 <host>
  ss -lntup | grep ':443'

About Port Reference Lookup

Port Reference Lookup preview - Networking tool

Look up common services for any TCP/UDP port number. Part of the DevTools Surf developer suite. Browse more tools in the Networking collection.

Use Cases

Identifying unknown services running on open ports during security audits
Verifying firewall rules reference the correct port numbers
Checking default database port numbers for connection configuration
Looking up registered ports for microservice deployment planning

Tips

Search by port number to find the associated service
Look up well-known ports below 1024 for common protocols
Verify which services use TCP vs UDP or both

Fun Facts

IANA maintains the official port number registry, with well-known ports (0-1023) requiring IETF approval for assignment.
Port 80 was assigned to HTTP by Tim Berners-Lee in 1991, while port 443 was assigned to HTTPS in 1994.
There are 65,535 available TCP and UDP ports per IP address, with ports 49152-65535 designated as dynamic/ephemeral ports.

FAQ

Which ports does it know?: Well-known ports (0-1023) fully, registered ports (1024-49151) for common services, ephemeral range (49152+) documented but not individually listed.
Is the list IANA-official?: Yes — matches IANA's registered services. Some ports have both official and common-convention uses; both are shown.
What's the difference between TCP and UDP ports?: Separate namespaces — port 53 TCP and port 53 UDP are different things. DNS uses both. The tool shows protocol per service.
Why is port 22 always SSH?: Registered with IANA in 1995. Changing SSH's port is possible (security through obscurity) but most tools default to 22.

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