Preventing Circumvention of Umbrella

If a device is configured to use DNS servers other than Umbrella's, it is possible to bypass any filtering rules configured for an organization. Fortunately, it is quite easy to create a firewall rule to block any DNS requests going to servers other than Umbrella:

Allow port 53 TCP/UDP traffic to 208.67.222.222 and 208.67.220.220
Block port 53 TCP/UDP traffic to all IP addresses (with lower priority than allowing traffic to Umbrella's DNS servers)

To request a firewall of this nature be put into place on a Networkmaine-provisioned EdgeRouter, please send an email to support@msln.net requesting the implementation of an Umbrella bypass block rule.

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