TeamViewer is remote access software. It has been designed to be easy to use, and thus doesn’t require you to open any TCP or UDP ports in order to use it. This article shows the ports used by TeamViewer, and explains how to block or allow these ports on your computer network.

Ports used by TeamViewer

The ports used by TeamViewer are TCP 80, TCP 443 and TCP 5938.

How to Allow TeamViewer Ports

You do not need to redirect any ports in order for TeamViewer to work. It will automatically find it’s way out of your network, unless it has been explicitly blocked. If you are having trouble, check if there are any outbound rules in your firewall for ports 80, 443 and 5938. Also check if you are using a HTTP proxy or HTTP transparent proxy – this could be intercepting and blocking your connection to TeamViewer’s servers.

How to Block TeamViewer Ports

If you want to block TeamViewer on your network, there are a number of ways to do this:

  1. Block Access to DNS Records
  2. Block Access to the TeamViewer IP Address Range
  3. Block outgoing access on TCP Port 5938 on your router/firewall
  4. Restrict the TeamViewer EXE from running, via Group Policy
  5. Deep packet inspection in your firewall

I have written a guide to help you block TeamViewer ports on your network, as well as other methods. Read the guide here.

I have also written an article comparing TeamViewer with different methods of remote access. Read it here.