Port 1026: Calendar Access Protocol — A Registered Ghost Service

What You're Looking At

Port 1026 is a registered port — one of 48,127 ports (1024-49151) that IANA manages for applications requesting a known, stable port number. This is different from well-known ports (0-1023) that are carved out for core Internet services like HTTP, DNS, and SSH.

The Official Story

Port 1026 is assigned to Calendar Access Protocol (CAP), registered in December 2010 by Doug Royer. It supports both TCP and UDP. That's the whole entry in the official IANA registry. ¹

The Reality

Despite being officially registered, Calendar Access Protocol on port 1026 sees virtually no real-world deployment. It's listed in network scanning tools and port databases, but you won't find it running on most systems. Port 1026 belongs to the thousands of registered services that exist in the IANA record but not on the actual Internet.

This happens often. A service gets registered, published in a registry, documented somewhere, and then either gets superseded by something better, never finds adoption, or gets replaced by a different protocol. The port number stays in the registry forever—it's the Internet's equivalent of a business license for a shop that closed years ago.

Registered Ports and Why They Matter

The registered port range (1024-49151) is where most application-level services live. When a new protocol needs a port number, IANA assigns it here through a formal review process. ² Once assigned, the port number becomes part of the permanent record.

This creates an interesting problem: IANA's port registry becomes littered with historical artifacts. Some are active and important. Some are ancient. Some, like port 1026, are officially correct but practically irrelevant.

How to Check What's on Port 1026

Use standard network tools to see if anything is actually listening:

# macOS or Linux - check if something is listening
lsof -i :1026

# Or scan the port on a specific host
nc -zv hostname 1026

# Network-wide scan (requires tools like nmap)
nmap -p 1026 hostname

On most systems, port 1026 will return "connection refused." Nothing is listening. That's normal.

Why Unassigned (But Registered) Ports Matter

Port 1026 illustrates something important about how the Internet actually works versus how it's supposed to work:

• The official story: IANA is the authority. The registry is truth. Every port has a purpose.
• The actual story: Most of the Internet ignores most of the registry. Thousands of registered ports see zero traffic.

This matters because it shows the difference between a protocol specification and real adoption. A port can be registered, documented, and "correct" without ever being used. The Port 1026 entry proves that following official procedures doesn't guarantee anything will actually use your port.

In practice, services take off when they solve a problem better than alternatives, not because they have an official port number. Port 1026 learned that lesson the hard way—by becoming a ghost service in a registry nobody reads.

Checking the Registry Yourself

You can look up any port in the official IANA registry: https://www.iana.org/assignments/service-names-port-numbers

Port 1026 will be listed, with all its official attributes. What won't be listed is that you'll never actually encounter it in the wild.

Related Ports

• Port 1025 — NFS or Blackjack (also quietly unused)
• Port 1027 — Flex License Manager protocol (more actively used in some enterprise environments)
• Port 135 — RPC Endpoint Mapper (actively used on Windows systems)
• Port 80 / 443 — HTTP and HTTPS (the ports that actually changed the world)