Port 2170: EyeTV — The Mac That Became Your DVR

Port 2170 is formally registered with IANA for EyeTV, a digital television application made by Elgato Systems for Mac. The registration came in November 2004, when USB TV tuner hardware was a novel idea and watching your home television from across the Internet felt genuinely futuristic.

What EyeTV Does

EyeTV combined a USB hardware tuner with Mac software to turn your computer into a DVR. You could record broadcast television, pause live TV, and — through port 2170 — stream that video to remote clients over the Internet.

The port handles communication between the EyeTV server (running on your Mac at home) and EyeTV clients (originally the iOS EyeTV app). When the iPhone app launched and you wanted to watch live TV from your phone while traveling, it knocked on port 2170.

EyeTV uses both TCP and UDP on this port. TCP handles the control channel — commands like "start streaming channel 5." UDP carries the video payload, where speed matters more than perfect delivery.

The Range This Port Lives In

Port 2170 sits in the registered ports range (1024–49151). This range is administered by IANA, and any software vendor can formally request a port assignment. Elgato did exactly that, giving EyeTV a permanent, official address in the port numbering system.

Registered ports aren't reserved in the way that well-known ports (0–1023) are — your operating system doesn't require root privileges to bind to them. But having an IANA registration means the port is officially documented and won't be accidentally assigned to something else.

EyeTV Today

Elgato sold the EyeTV software business to Geniatech in 2016 and refocused on streaming hardware (capture cards, now popular with streamers). Geniatech continues EyeTV under the same name.

Port 2170 persists in EyeTV documentation and port forwarding guides. If you have an older EyeTV setup, your router may still have a forwarding rule pointing at this port.

If You See Port 2170 Open

On a Mac running EyeTV Server mode, seeing port 2170 listening is expected. On any other machine, it's worth investigating.

# macOS / Linux — see what's listening on port 2170
lsof -i :2170

# Windows
netstat -ano | findstr :2170

# Check if a remote host has port 2170 open
nmap -p 2170 <hostname>

If nothing is running EyeTV and this port is open, something else has claimed it. Worth knowing what.