One of the mechanisms used by Cisco Meraki devices to check connectivity status is DNS. As such, it is important to ensure that Cisco Meraki devices are configured to use valid DNS servers in their WAN IP configuration. This article describes best practices for configuring DNS servers on the WAN interfaces of all Cisco Meraki products.
One of the most common DNS configurations when assigning a static IP address is to use one ISP-provided DNS server and one well-known public DNS service such as Google (220.127.116.11). Many ISPs maintain their own hosted DNS server and may not have all records or have lookups to many publicly-accessible servers. In practice, it is good to configure two different DNS servers, as demonstrated in the image below (taken on the Local Status Page of an MX appliance):
These DNS servers are used by the Meraki device to check Internet connectivity, check into Dashboard, load content lists, and register VPN connections, among other services. Therefore, DNS servers are a critical component for correct operation of the device, and it is strongly recommended that both DNS server fields be populated.
Note: These DNS servers are only used by the Cisco Meraki device for its management traffic and connectivity tests. Downstream clients will not use these servers unless configured within DHCP.
For more information on internet connectivity testing, please refer to our article on connection monitoring.