Teamviewer Firewall Whitelist May 2026

You are whitelisting the destination , not the port. If you allow port 5938 to "Any" IP address, malware on your network could use that port to exfiltrate data to a bad server in Russia.

| Protocol | Port(s) | Destination | Purpose | | :--- | :--- | :--- | :--- | | TCP | 443 | *.teamviewer.com | Web login & authentication | | TCP | 5938 | *.teamviewer.com | Primary data channel | | TCP | 80 & 443 | master.teamviewer.com | Fallback & master routing | teamviewer firewall whitelist

In 90% of cases, the culprit is a strict firewall. You are whitelisting the destination , not the port

Few things are more frustrating in IT support than the dreaded "Connection failed. Partner did not connect to the router." error message. Few things are more frustrating in IT support

You’ve checked the internet. The remote computer is powered on. TeamViewer is running. So, what gives?

Whitelisting means telling your firewall: "Do not inspect, block, or question traffic coming from TeamViewer’s official servers. Let it pass immediately."

If you run a corporate network, use a hardware firewall (like SonicWall or Fortinet), or have aggressive antivirus software, you need to whitelist TeamViewer. You cannot simply rely on UPnP (Universal Plug and Play) or hope the traffic slips through.