What This Port Number Means
Port 10005 lives in the registered port range (1024-49151). This range exists in the gap between system ports (0-1023, reserved for operating systems and well-known protocols) and ephemeral ports (49152-65535, used temporarily by client software).
Registered ports are meant for applications. Companies and developers can request official assignments from IANA—the Internet Assigned Numbers Authority—but the process is slow, and the backlog is long. Port 10005 has no official assignment. It's on the registry, available, but unclaimed.
And yet it's not empty.
What Actually Uses Port 10005
In practice, port 10005 has been colonized by enterprise software:
Veeam Backup & Replication uses port 10005 for agent-to-server communication in its backup system. When Veeam Agent for Windows connects to a Veeam Backup & Replication server, this is the port it attempts. 1
Siemens Logo! protocol, used for controlling Siemens programmable logic controllers (PLCs), communicates over TCP port 10005. Industrial systems depend on this port without it being formally registered. 2
Qualys Cloud Agent, a vulnerability scanner, has been observed listening on port 10005, creating conflicts with Veeam. 1
Dialogic Diva HTTP interface also uses this port for web administration. 3
None of these services registered port 10005 with IANA. They simply chose it, and because it wasn't officially assigned, they got away with it. Now they're stuck with it, and it's difficult to change without breaking backwards compatibility across millions of systems.
How to Check What's Listening
To see what—if anything—is listening on port 10005 on your system:
Windows:
macOS/Linux:
The output will show you the process ID (PID) and which application claimed the port. If nothing appears, port 10005 is silent on your machine.
Why Unassigned Ports Matter
The registered port range is a commons. Unlike well-known ports, where the rules are strict and documented, the registered range lets software make local decisions. This creates a kind of Tragedy of the Commons: each application picks a port that seems free, and you end up with 65,000 doors to choose from but eventually they start colliding.
Port 10005 collisions between Veeam and Qualys are documented in their support forums, which means this is real operational pain for real people. 1
The Internet assigns specific ports for important reasons—to prevent exactly this kind of confusion. Port 10005 should probably be registered by one of its de facto users, standardizing what the rest of the network expects to find there. Instead, it remains in limbo: officially unassigned, practically occupied, and occasionally fought over.
Related Ports
- Port 10001 — Sometimes used instead of 10005 by Veeam in different configurations
- Port 443 — The official port for HTTPS (contrast: well-known, universally understood)
- Port 1024 — The first port in the registered range, the beginning of the commons
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