What Port 3576 Is
Port 3576 sits in the registered ports range (1024–49151). These ports are assigned by IANA on request — a company or project files an application, gets a number, and that number is theirs.1
In 2002, a company called Coalsere, Inc. claimed port 3576 for something called "CMC Port" — likely a Cluster Management Console for their data management and network storage software.2 The service name in the IANA registry is cmc-port. It covers both TCP and UDP.
That's essentially all that's known. Coalsere does not appear to have a surviving web presence. Their products left no notable documentation trail. The port is officially theirs and practically no one's.
What "Registered" Actually Means
Registration doesn't mean a port is in use. It means someone asked for it, and IANA recorded the claim. The registered range exists to prevent collisions — so that two different products don't independently decide to use the same port and step on each other.
A registered port with a defunct registrant is common. Software companies die. Products get abandoned. The IANA list doesn't prune itself. Port 3576 joins a long list of numbers that are technically allocated but functionally empty.
What You Might Find Here
If you see traffic or a listening service on port 3576, it almost certainly isn't Coalsere CMC. It could be:
- A custom application that picked this port arbitrarily
- Malware using an obscure port to avoid detection
- A developer using it temporarily for a local service
None of those are the registered use. That's fine — this is how the registered range works in practice.
How to Check What's Listening
On Linux or macOS:
On Windows:
If something is listening, the process ID will tell you what it is. If nothing is listening, this port is exactly what it looks like: empty.
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