PHP: Block MAC Address

TL;DR

This guide shows you how to block a specific MAC address using PHP by checking it against a list and preventing access if found. This is useful for basic device control on your network, but remember this is server-side only – clients can spoof their MAC addresses.

Steps

1. Create a Blocked MAC Address List

First, you need a list of MAC addresses to block. This could be stored in a file, database, or directly within your PHP code (though that’s less flexible). For simplicity, we’ll use an array.

2. Get the Client’s MAC Address

This is the tricky part. PHP doesn’t have a built-in function to reliably get the client’s MAC address directly. You’ll need to rely on information passed by the client, which can be spoofed.

Common methods (with caveats):

• From HTTP Headers: Some devices pass their MAC address in custom headers.
• Using JavaScript: You can use JavaScript to attempt to get the MAC address and send it to your PHP script. This is unreliable due to browser security restrictions.
• Network Interface Information (Server-Side): If you have access to the server’s network interface information, you might be able to correlate IP addresses with MAC addresses, but this isn’t a direct client MAC address retrieval method.

For demonstration purposes, let’s assume we receive the MAC address via a GET request parameter named mac_address.

3. Retrieve and Validate the MAC Address
4. Check Against the Blocked List

Now, compare the retrieved and validated client’s MAC address against your blocked list.

5. Complete Example

Putting it all together:

6. Important Considerations
• Spoofing: Clients can easily spoof their MAC addresses. This method is *not* a secure way to control access. It’s suitable for basic filtering, but don’t rely on it for security-critical applications.
• Privacy: Collecting and storing MAC addresses may have privacy implications. Be transparent with your users about data collection practices.
• Reliability of Retrieval: Getting the client’s MAC address reliably is difficult. The method you choose will depend on your specific environment and network setup.