Port 610 occupies an interesting position in the port numbering system. It's officially assigned to a real service, but that service is obscure enough that you've probably never encountered it.
What Is Port 610?
Port 610 is assigned to npmp-local—the local management component of the Network Peripheral Management Protocol (NPMP).12 This protocol is part of a suite that includes:
- Port 609: npmp-trap (for NPMP trap messages)
- Port 610: npmp-local (for local management)
- Port 611: npmp-gui (for graphical interface management)
Both TCP and UDP protocols are registered for port 610.3
The Well-Known Ports Range
Port 610 sits in the well-known ports range (0-1023), also called system ports. These are the prestigious addresses of the Internet—reserved by IANA for established services and protocols.4
To listen on port 610, a program typically needs administrative privileges on Unix-like systems. This is by design. The well-known range is protected to prevent random applications from impersonating important services.
But here's the strange thing: despite being in this protected range, NPMP is obscure enough that finding detailed documentation about what it actually does requires real digging.
What Does NPMP Do?
NPMP stands for Network Peripheral Management Protocol. Based on the limited available documentation, it appears to be designed for managing network-attached peripherals—printers, scanners, and similar devices.5
But unlike SNMP (Simple Network Management Protocol), which is ubiquitous and well-documented, NPMP never achieved widespread adoption. It exists in the official registries, occupies three adjacent well-known ports, and yet remains practically invisible in modern networking.
Is Anything Actually Using Port 610?
In practice, port 610 is rarely seen in active use. Some sources reference it in connection with Mac OS X RPC-based services,6 but even this connection is poorly documented.
The protocol serves as a reminder that not every assigned port number carries the weight of HTTPS or SSH. Some protocols get registered, claim their space in the numbering system, and then fade into obscurity.
Checking What's Listening on Port 610
If you want to see whether anything is using port 610 on your system:
On Linux or macOS:
On Windows:
Using nmap to scan a remote system:
Most of the time, you'll find nothing. Port 610 is typically silent.
Why Unassigned and Obscure Ports Matter
The story of port 610 illustrates something important about the port numbering system: it's a finite resource with 65,535 possible values, and not all assignments age equally well.
Some protocols—HTTP, HTTPS, SSH, DNS—become fundamental to how the Internet works. Others get assigned with good intentions but never gain traction. The well-known ports range is full of both kinds.
Port 610 exists as a kind of archaeological artifact. Someone, at some point, thought network peripheral management was important enough to deserve three consecutive well-known ports. The protocol was registered. The ports were assigned. And then time moved on.
Related Ports
- Port 609 — npmp-trap (NPMP trap messages)
- Port 611 — npmp-gui (NPMP graphical management)
- Port 161/162 — SNMP (Simple Network Management Protocol, the widely-used alternative)
Frequently Asked Questions About Port 610
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