Configure WPAD in DNS for automatic proxy detection with SecureSchool.

Summary #

Proxy Auto Detect, also known as WPAD (Web Proxy Auto-Discovery Protocol), allows browsers and devices to automatically download a proxy configuration file (wpad.dat / proxy.pac).

This is useful in environments where you cannot rely on Group Policy, login scripts, or manual browser configuration. WPAD works seamlessly across:

• Windows devices (workstations, laptops, servers)
• Chromebooks
• macOS and iOS devices
• Android devices

Advantages:

• Devices automatically detect and use SecureSchool’s proxy when on the school/work network.
• When taken off-network (e.g., at home), the proxy auto-detect fails gracefully, allowing Internet access without additional changes.

Note: Without WSUS or centralized update management, enabling WPAD may cause all Windows devices to download updates directly from Microsoft, potentially consuming significant bandwidth. We strongly recommend configuring Windows Server Update Services (WSUS) or a similar update management solution before deploying WPAD.

Step 1. Allow DNS to Answer for “wpad” #

By default, Windows Server DNS blocks the wpad hostname for security reasons. You must allow it:

1. On each DNS server, run regedit.
2. Browse to:
3. HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\DNS\Parameters
4. Edit the GlobalQueryBlockList value.
5. Remove wpad from the list.
6. Close the editor.
7. Restart the DNS Server service.

Step 2. Create the “wpad” A Record #

1. Open DNS Manager (Server Manager > Tools > DNS).
2. Expand Forward Lookup Zones > [Your Domain].
3. Right-click your domain > New Host (A or AAAA).
4. In the Name field, enter: wpad
5. In the IP address field, enter the IP of your SecureSchool appliance.
6. Uncheck Create associated pointer (PTR) record.
7. Click Add Host.
8. Repeat on all DNS servers in your network (if not automatically replicated).

Step 3. Test Proxy Auto Detect #

1. On a client machine, remove manual proxy settings from the browser.
2. Enable Automatically Detect Settings (exact wording varies by browser).
3. Browse to any website.
   • If configured correctly, the device will automatically fetch http://wpad.[yourdomain]/wpad.dat from SecureSchool.

Once complete, all devices that support WPAD will automatically use SecureSchool’s proxy, ensuring consistent filtering without manual setup.

References #

• Microsoft: Configure proxy server settings in Windows (WPAD via DNS/DHCP) Microsoft Learn
• Microsoft: How the Windows Update client determines which proxy server to use
• K12USA: Windows Server Group Policies for Proxy Auto Configuration