Split DNS
Overview
Some deployments may require that DNS queries for specific domains be directed to specific DNS servers. This is often the case when a public-based DNS service, such as OpenDNS, is desired for most DNS queries, but local name resolution is needed for internal resources or applications
The functionality discussed in this article is only available in closed beta. If you are interested in participating in this beta, please contact your Cisco Meraki sales rep.
Feature
When split DNS is configured on an MX appliance, the MX will snoop DNS traffic. DNS queries that match the configured domains for split DNS are intercepted and redirected to the configured DNS server. These redirected DNS requests will be transmitted to the configured server in accordance with the MX's routing behavior.
The responses to these DNS queries are also intercepted by the MX and routed back to the client that issued the original DNS request.
The MX must see the client's DNS requests and the server's response in order to properly redirect DNS requests to the configured DNS server and route the responses back to the client issuing the DNS request.
Limitations
The split DNS feature does not currently support redirection through CNAMEs. If a client does a query for the A record of FOO, but learns of BAR, a canonical name for FOO, a subsequent A record query for BAR will not be redirected unless BAR is also configured as a split DNS domain. Additionally, BAR will not be recognized and treated as an alias for FOO.
Split DNS only supports redirecting DNS requests to one DNS server.