Port 3508 — Unassigned (Genesys PureConnect)

Port 3508 sits in the registered port range (1024–49151). IANA maintains this range for services that have applied for an official assignment — but port 3508 has no assigned service. On paper, it's empty.

In practice, it isn't.

The Registered Port Range

Ports 1024 through 49151 are the middle tier of the port number space. Below them, the well-known ports (0–1023) hold the Internet's foundational protocols: HTTP on 80, HTTPS on 443, SSH on 22, DNS on 53. Those assignments are locked and globally recognized.

Above them, the ephemeral ports (49152–65535) are temporary — your operating system hands them out dynamically whenever you open a connection, then reclaims them.

The registered range is different. These ports are meant for specific applications that have asked IANA to reserve a number so their software has a predictable home. The registration is voluntary. Not every piece of software that picks a port in this range files the paperwork. Port 3508 is one of those.

Observed Use: Genesys PureConnect

Genesys PureConnect (formerly Interactive Intelligence) uses port 3508 as the default HTTPS port for its Interaction Web Tools component.¹ This is enterprise contact center software — the kind that routes customer service calls, manages chat queues, and powers the "Chat with an agent" button on large company websites.

In a PureConnect deployment, the web server (running IIS or similar) connects back to the CIC (Customer Interaction Center) server over port 3508 for encrypted communication. Port 8114 handles the unencrypted equivalent. Neither port is IANA-registered — Genesys simply picked them and documented them in their installation guides.

If you see port 3508 open on a server, there's a reasonable chance it's part of a contact center deployment.

How to Check What's Listening

# On Linux/macOS
sudo ss -tlnp | grep 3508
sudo lsof -i :3508

# On Windows
netstat -ano | findstr :3508
# Then match the PID: tasklist | findstr <PID>

# With nmap (from another machine)
nmap -sV -p 3508 <target>

The -sV flag tells nmap to probe the port and attempt to identify the service, not just confirm it's open.

Why Unassigned Ports Matter

The port number system only works because it's a shared convention. When a server listens on port 443, every client on Earth knows to speak HTTPS there. That agreement is why the Internet is interoperable.

Unassigned ports break that agreement in a small way. Software that squats on an unregistered port creates ambiguity — two applications might independently choose the same number, or security teams might not know what to expect when a port shows up in a scan. The registration process exists to prevent these collisions.

Port 3508 is harmless. But it's a small example of how the port registry works in theory versus practice: IANA offers a reservation system, and enterprise software sometimes just picks a number and ships.