You might need to look into other options. By externally accessible do you mean from different locations?
Another method to differentiate between external and internal clients is by using client subnets as a criteria. If you can identify the subnets to which the internal clients belong, you can configure DNS policy to differentiate based on client subnet. For information on how to configure traffic management using client subnet criteria, see Use DNS Policy for Geo-Location Based Traffic Management with Primary Servers.
Use DNS Policy for Geo-Location Based Traffic Management with Primary Servers
Hope this resolves your Query !!
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