Troubleshooting Blocking

ActivTrak blocks websites by writing to the hosts file and redirecting web traffic based on what the Admin on the account has chosen to block. A user may be able to bypass this blocking if the hosts file cannot be written to. This is typically caused by anti-virus blocking the agent from modifying the hosts file but can be fixed by whitelisting the necessary file paths. To learn more about whitelisting file paths on the antivirus click here.

NOTE: It can take up to 20 minutes for changes in the blocked domain list to take effect on the computers with ActivTrak installed. This article provides a step-by-step guide on how to speed up this process by flushing the DNS.

Flushing DNS After Making Changes:


  • Navigate to the Windows Search bar, then type “cmd“.
  • Right-click “Command Prompt“, then choose “Run as Administrator“.
  • Type ipconfig /flushdns then press “Enter“. (be sure there is a space before the slash)



  • Open Terminal
  • type the following strings and hit return after each one 
    • sudo killall -HUP mDNSResponder
    • sudo killall mDNSResponderHelper
    • sudo dscacheutil -flushcache

Flushing DNS After Uninstalling the ActivTrak Agent:

The agent will remove any ActivTrak-written entries to the hosts file when uninstalled, but in the rare case the uninstaller fails to remove them, it may be necessary to reset the hosts file manually. 


  1. Search for “Notepad” using the Windows search bar, and then tap or click the Notepad icon.

  2. Copy the following text, and then paste the text into the file:
    # Copyright (c) 1993-2006 Microsoft Corp.
    # This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
    # This file contains the mappings of IP addresses to host names. Each
    # entry should be kept on an individual line. The IP address should
    # be placed in the first column followed by the corresponding host name.
    # The IP address and the host name should be separated by at least one
    # space.
    # Additionally, comments (such as these) may be inserted on individual
    # lines or following the machine name denoted by a '#' symbol.
    # For example:
    #          # source server
    #              # x client host
    # localhost name resolution is handle within DNS itself.
    #       localhost
    #       ::1             localhost 
  3. On the File menu, select Save as, type "hosts" in the File name box, and save the file to the desktop.
  4. Close Notepad.

  5. Search for %WinDir%\System32\Drivers\Etc using the Windows' search bar, and then select the File folder icon.

  6. Tap and hold or right-click the Hosts file, select Rename, and then rename the file as "Hosts.old".

  7. Copy or move the Hosts file that you created in step 3 from the desktop to the %WinDir%\System32\Drivers\Etc folder. If you are prompted to enter an administrator password, select Continue.


  1. Open Terminal and type "sudo nano /etc/hosts/ and press return.

  2. Enter your administrator password and then hit return. Note: you will not see any characters appear on the screen when typing your password.

  3.  Use the screen that comes up to remove the ActivTrak entries from your hosts file.
  4. After you are done editing the hosts file, save it and run the commands listed above to flush the DNS on your Mac.



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