Port 1423 sits in a strange space. It's never been officially assigned by IANA. No RFC defines what should run here. And yet thousands of enterprises around the world run Oracle Essbase on this port, have been doing so for decades, and will likely continue doing so for years to come.
This is how the registered port range actually works—not by official decree, but by whoever ships first and sticks around.
What Runs on Port 1423
Oracle Essbase Agent uses port 1423 as its default communication port. Essbase is a multidimensional database system (often called an OLAP database) used for business analytics, planning, budgeting, and forecasting.1
When an Essbase client connects to an Essbase server, the first conversation happens on port 1423. The client asks the Agent: "Where are the databases?" The Agent responds with connection details for the specific Essbase servers and applications the client needs.
Think of port 1423 as the reception desk for Essbase. You arrive at 1423, and the Agent directs you to the right place.
The Registered Port Range
Port 1423 falls in the registered port range (1024-49151). These ports are:
- Not privileged—any user can open them without special permissions
- Meant to be registered with IANA for specific services
- Often claimed by software vendors without formal registration
- Subject to conflicts if two applications choose the same port
The registered range is a middle ground between the strict control of well-known ports (0-1023) and the chaos of ephemeral ports (49152-65535). It's where most application-specific services live.
How Essbase Claimed This Port
Essbase started life in the early 1990s as Arbor Software's flagship product. When they needed a port number, they picked 1423. There was no formal registration process that mattered—they shipped the software, wrote "default port: 1423" in the documentation, and that was that.2
Oracle acquired Essbase (through the Hyperion acquisition in 2007), and the port number stayed. Now it's locked in. Changing the default would break existing installations, firewall rules, and decades of documentation.
This is how ports get claimed in practice. First to ship wins.
Security Considerations
Port 1423 has appeared in old Trojan and malware databases, but this is misleading. Any port can be used by malware—listing 1423 as "dangerous" just means someone once wrote malware that used it.3
The actual security considerations for Essbase are:
Don't expose port 1423 to the Internet. Essbase is an internal enterprise system. If port 1423 is open to the public Internet, something is misconfigured.
Essbase supports TLS. The secure Agent port defaults to 6423. If you're running Essbase in production, you should be using encrypted connections.
Authentication matters more than the port. Essbase has its own authentication system. The port number is just where the conversation happens—the security comes from what's required to join that conversation.
Checking What's Listening
To see if something is listening on port 1423:
On Linux/Mac:
On Windows:
If you see something on 1423 and you're not running Essbase, investigate. It could be another application that chose the same port, or it could be something that shouldn't be there.
Why Unassigned Ports Matter
The registered port range is full of ports like 1423—claimed by practice, not by official assignment. This creates a weird ecosystem:
- No central authority ensures uniqueness
- Port conflicts are possible if two applications choose the same number
- Documentation becomes the standard—if Oracle says Essbase uses 1423, that's what matters
- Changing is costly—once a port is in production across thousands of sites, it's effectively locked in
Port 1423 works because Essbase got there first and stayed around. If another major application had picked 1423 in the 1990s, we'd have a conflict. But that didn't happen. Essbase claimed it, and the claim stuck.
This is how the Internet actually gets built—not through perfect planning, but through a combination of standards, squatting, and luck.
Frequently Asked Questions
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