Exposed RDP is one of the most common ways attackers get into networks: internet-wide scans find open 3389 ports within hours, and stolen or guessed passwords do the rest. If you need remote access to a Windows PC from your Mac, connect through a VPN or Tailscale rather than forwarding the port.
Facts
- Port
- 3389
- Protocols
- TCP, UDP
- Service
- RDP
What uses port 3389
Remote Desktop (RDP) servers on Windows. TCP 3389 carries the session; newer versions also use UDP 3389 for better performance.
On a Mac
A Mac connects out to 3389 when you use the Windows App (formerly Microsoft Remote Desktop) to reach a Windows machine. Macs don't listen on 3389; their own screen sharing uses VNC on 5900.
sudo lsof -nP -iTCP:3389Security
RDP exposed to the internet is a top target for ransomware groups. Put it behind a VPN or gateway, never forward 3389 directly.
Frequently asked questions
How do I connect to port 3389 from a Mac?
Install Microsoft's Windows App (previously Microsoft Remote Desktop) from the App Store and add the PC by its address.
Is it safe to open port 3389?
Not to the internet. Exposed RDP is heavily attacked. Use a VPN or a Remote Desktop Gateway.
Does Mac screen sharing use port 3389?
No. macOS Screen Sharing uses VNC on port 5900. 3389 is Windows RDP only.