By starting the connection from inside your network, the software bypasses the need for port forwarding (NAT) on your router.
For the most up-to-date information, please refer to the official TeamViewer documentation: https://www.teamviewer.com/en-us/ teamviewer port
If port 5938 is blocked, TeamViewer will automatically attempt to use . By starting the connection from inside your network,
, which serves as the backbone for its high-performance remote control and data transfer capabilities. Beyond a simple technical requirement, the design of TeamViewer's port usage reflects a sophisticated architecture focused on balancing user accessibility with network security. The Primary Gateway: Port 5938 Port 5938 is the preferred channel for TeamViewer because it is optimized for stability and speed. Unlike standard web traffic, this port is dedicated to the proprietary protocols that encapsulate remote display data and input control commands. By utilizing this specific port, TeamViewer minimizes the overhead associated with general web protocols, allowing for more fluid real-time interactions. In corporate environments, security teams often whitelist this specific port to ensure IT support can function efficiently without compromising the rest of the network's security posture. Resilient Fallback Mechanisms A defining feature of TeamViewer is its ability to "find its way out" of restrictive networks. If port 5938 is blocked by a firewall, the software automatically attempts to connect via: TCP Port 443: Typically used for HTTPS traffic, this fallback is also utilized for custom module deployments and update checks. TCP Port 80: As a last resort, TeamViewer can use standard HTTP. However, this connection is notably slower and lacks automatic reconnection features if the link is dropped. 10 sites Ports and URLs used by TeamViewer Aug 14, 2025 — Beyond a simple technical requirement, the design of
Most people think TeamViewer just “magically works” using the ID and password. But behind the curtain, it relies on specific network ports. If those ports are blocked, your remote session dies instantly.
For the best experience, your firewall should allow outbound TCP and UDP traffic on port 5938. 2. Port 443 (TCP) – The Standard Fallback