Port 597: PTC Name Service — A corporate protocol in the well-known range

Port 597 is officially assigned to PTC Name Service, a protocol used by PTC Inc.'s product lifecycle management software suite. Unless you're working with CAD software, manufacturing systems, or IoT platforms from PTC, you'll probably never see traffic on this port.

What runs on this port

Service: PTC Name Service (ptcnameservice)
Protocols: TCP and UDP
Official assignment: IANA-registered, contact Yuri Machkasov¹

PTC Name Service is an internal naming and directory service used by PTC's software products—including Creo (CAD software), Windchill (product lifecycle management), and ThingWorx (IoT platform). These tools are used by engineers at companies that design complex products: aircraft, automobiles, medical devices, industrial equipment.

The protocol handles name resolution and service discovery within PTC's software ecosystem. Think of it as a specialized phone book that helps different PTC applications find and talk to each other across a network.

Who is PTC?

PTC Inc. (formerly Parametric Technology Corporation) is a Boston-based software company founded in 1985. They make tools for designing, manufacturing, and maintaining physical products. If you've ever wondered how Boeing designs a 787 or how John Deere manages IoT data from tractors in the field, there's a decent chance PTC software is involved.²

Their software is specialized, expensive, and deployed in enterprise environments where engineers collaborate on complex product designs. Port 597 exists to support that infrastructure.

The well-known port paradox

Here's the strange part: port 597 sits in the well-known port range (0-1023), the prestigious real estate reserved for fundamental Internet services. Ports in this range are supposed to be assigned to protocols that matter broadly—HTTP, DNS, SSH, services that shape how the Internet works.

Port 597 is not that. It's a corporate protocol, used by a specific company's software, assigned a well-known port number. This happened during an era when IANA port assignments were less scrutinized, and companies could request port numbers for proprietary protocols.

It's official. It's registered. But it's essentially a private driveway with a prestigious address.

Security considerations

Port 597 should not be exposed to the Internet. PTC Name Service is designed for internal enterprise networks where PTC software is deployed. If you see traffic on this port from external sources, either:

• Someone is running PTC software and misconfigured their firewall
• Something is probing for services (port scanners often check well-known ports)
• Malware has used this port in the past for command-and-control (trojan activity has been observed, though not widespread)³

Check what's listening:

# Linux/macOS
sudo lsof -i :597
sudo netstat -tulpn | grep :597

# Windows
netstat -ano | findstr :597

If you're not running PTC software, nothing should be listening on port 597.

Related ports

PTC software uses multiple ports for different components of its suite. Port 597 is just one piece of a larger infrastructure. Other PTC-related ports may appear in enterprise environments where their software is deployed.

Why unassigned well-known ports matter

Most well-known ports (0-1023) are assigned to protocols everyone uses. But scattered among them are ports like 597—assigned to niche corporate protocols, legacy services, or long-dead experiments.

These ports matter because they represent the history of the Internet's growth. In the early days, getting a well-known port assigned was easier. Companies requested them, IANA granted them, and now we have this mixed neighborhood where fundamental protocols live next to proprietary corporate infrastructure.

Today, new well-known port assignments are rare and heavily scrutinized. Port 597 is a relic of a different era—when the Internet was smaller, more trusting, and nobody imagined we'd run out of numbers.