Advanced DHCP Configuration with MAC Address Filtering and Custom Options in Sophos

Hello Sophos Community,

I am currently working on a sophisticated DHCP setup on my Sophos system and need some advice on how to achieve specific configurations. Any guidance or insights from the community would be greatly appreciated.

My goal is to apply custom DHCP options based on the MAC addresses of certain network devices. Here’s a detailed view of what I am trying to accomplish:

1. MAC Address Filtering: I need to filter devices based on their MAC addresses. The specific patterns I’m interested in are:

   • 7C:2F:80
   • 00:21:04
   • 58:9E:C6

2. Custom DHCP Option for Specific MAC Addresses: For devices matching these MAC addresses, I wish to assign a special DHCP option. For example, assigning a default URL like: option default-url "http://[censored_url]/prov/".

In addition to the above, I have a specific query regarding the implementation of a DHCP class in Sophos:

Implementation of a DHCP Class Example:

class "snom" {
match if substring (hardware, 1, 3) 00:04:13;
option tftp-server-name "http://[censored_url]/settings.php?mac={mac}";
}

In this example, how is the MAC address passed at the end of the URL? Does the DHCP server automatically read the MAC address from the Snom device and insert it into the URL variable, or is this handled differently?

My main questions are:

• Does Sophos support such specific MAC address-based DHCP configurations, and if so, how can I configure this?
• How does Sophos handle the dynamic inclusion of MAC addresses in DHCP options, like in the 'snom' class example above?

I have not been successful in my initial attempts and am unsure if my approach aligns with Sophos capabilities. Detailed steps, advice, or references to specific Sophos documentation would be incredibly helpful. Thank you in advance for your assistance and time.

Thanks.