How to properly block TeamViewer

TeamViewer is the most convenient and practical program for remote access to other computers. At the same time, its use carries a certain risk: easy connection to other devices can lead to unauthorized use of information and identity theft. To protect yourself from such threats, you should know how to quickly block TeamViewer on your computer.

Is it possible to block TeamViewer

The program can be especially dangerous for commercial use, since any Internet connection can be a threat to the company’s information security. Most often, this applies to devices that act as a DNS server: they contain all the information that other computers use within the work network. Blocking in this case must be performed from the administrative device in order to stop unattended access on all computers.

Lock options

There are several effective methods to block TeamViewer from actively using computer resources. The easiest way is to work with special software that makes it easy to set up network access. Standard Windows tools are more difficult to use, but they block the app no less effectively.

Kerio control

It is easiest for server owners to work with the business version of the Kerio Control firewall. To restrict access to TeamViewer, just download its free version (access for 30 days) and follow these steps:

  1. Open the “Connections” section.
  2. Find and mark all active connection lines that contain format information:
  3. HTTP: GET http://”AAA”/din.aspx?s=”CCC”&id=”BBB”&client=DeynGate&p=”CCC” where:
    • “AAA” is the IP address of the TeamViewer server;
    • “BBB” is the ID of the device connected to TeamViewer;
    • “CCS” is any random number.
  4. Click the “Create a rule” button in which you need to set a ban on accessing the selected addresses.

The program is convenient in that it completely blocks TeamViewer from connecting to servers on each of the computers. When connecting new devices to the network, it is enough to add a new address to the list so that the general rule applies to it.

Mikro Tik

Mikro Tik software for setting up network equipment is suitable for servers of the same manufacturer.

How to properly block TeamViewer

Standard system tools allow you to disable TeamViewer access at the port level, that is, for each dependent device individually.

To complete the setup, you will need:

  • Open the “Server” section, select an administrative device.
  • Select the menu “Prohibition of launching the application”, then the line “TeamViewer”.
  • Open the line “Block port” and enter the code of the following format: /ip firewall filter add action=reject chain=forward dst-port=1234 protocol=tcp reject-with=tcp-reset, where 1234 is a four-digit port number.
  • Save the established rule.
  • Restart TeamViewer.

You will need to block each port separately, so you should first collect the entire list of ports, and then add new rules one by one to block TeamViewer’s access to them.


Users of server operating systems based on Linux can solve the problem of TeamViewer access to devices using the built-in Iptables tool. It is controlled through the terminal. The main difficulty of the process is that the program is provided with remote access without a dedicated IP address.

Blocking is done using a complex code that automatically blocks all incoming IP addresses generated on the TeamViewer server. In the terminal, enter the following lines one by one:

  • list=$(for i in $(seq 10); do dig +short ping$; done)
  • list2=$(for i in $(seq 10); do dig +short master$; done)
  • for i in $(echo $list | sed -e ‘s/ /,/g’); do
  • for j in $(echo $list2 | sed -e ‘s/ /,/g’); do
  • for k in $(dig +short; do
  • iptables -A FORWARD -d $i,$j,$k -j DROP;
  • done done done

Using commands allows you to block all incoming from the main domain Due to this, the program’s access to all devices is completely blocked.

Other means

Windows server editions natively allow you to spoof incoming IP addresses from the domain. To do this, follow these steps:

  • Open “DNS Manager” through the “Apps and Features” menu in the Control Panel or the “Administrative Tools” panel in the Start menu.
  • Go to the “Forward View Zones” folder, then to “”.
  • Create a new entry with an empty “Name” field and an IP address of

You can also use the AppLocker tool (found in “Application Control Policy” in Security Settings) by creating a rule to block the program. But this method is unreliable, since the latest version of TeamViewer easily bypasses the restriction by generating new IP addresses.

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Mike Lombardi/ author of the article

QA engineer, head of automated software testing department. Knowledge of Java, C/C++, JSP, HTML, XML, JavaScript, SQL and Oracle PL/SQL. Journalist and columnist in the IT field. Website creator and administrator.

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