In order to use the Barracuda DNS Filtering Service with Barracuda Content Shield, you must direct your router, firewall, or your computer(s) (laptop / desktop) to the assigned Barracuda Domain Name Server (DNS). The IP address for the Barracuda DNS nameserver is shown on the Configure DNS step (3) of the Add Location popup, which you access on the DNS FILTERING page.
Ensure DNS Traffic Is Routed from Clients to the Barracuda DNS Nameserver
Use one (or more) of the methods below. It is easier to configure the primary DNS nameserver at the network level rather than to configure on every client machine. You can also create a policy that only allows DNS requests to the Barracuda DNS nameservers as a means of preventing users from circumventing the service. You can also use a GPO or similar RMM tool to lock the DNS nameserver settings from being modified by end users.
Using a Barracuda Firewall or other firewall solution: Configure your Barracuda NG Firewall or Barracuda CloudGen firewall solution to determine which DNS requests are for internal domains and process those, but restrict external DNS requests from clients to Barracuda DNS nameservers. For the Barracuda CloudGen Firewall, see the article on DNS which describes using the Barracuda CloudGen Firewall as a DNS server. Also see How to Configure DNS settings for the Barracuda CloudGen Firewall configuration.
- Configure your router: It is easier to configure the primary DNS nameserver on the router for the network than to configure on all client machines, and this prevents users from circumventing DNS settings. Follow general instructions for routers.
- each client machine: See general instructions for your operating system below. You must also secure the settings on your clients so that users cannot change their local DNS server IP addresses.