This solution applies to Barracuda SSL VPNs, all firmware versions.
Enabling valid external hostnames can help secure your Barracuda SSL VPN. The feature prevents users from accessing the web interface except through whatever hostname is specified by the administrator, and may assist in deterring users who, for example, attempt to connect to the Barracuda SSL VPN's IP address after a port scan. To enable this feature, follow the below steps.
- Go to Advanced > Configuration.
- In the Web Server section, enter the hostname on which to accept connections in Valid external hostnames.
- Change the Invalid hostname action to Refuse all requests using invalid hostname.
- If you wish to force a redirection of the user instead of rejecting the request, change the Invalid hostname action to Redirect to valid hostname. This will nullify any security benefit, but may be desirable as a method to enforce uniformity.