You can now use Amazon CloudWatch to see query volume metrics for Amazon Route 53 Resolver endpoints, including the aggregate number of queries that are handled by an outbound Resolver endpoint. This aggregate metric combines query counts from all accounts that are using shared conditional forwarding rules associated with the outbound Resolver endpoint. Additionally, you can view query volume metrics for each IP address that is associated with an inbound or outbound Resolver endpoint. This gives you an even more granular view of how query traffic is flowing amongst the IP addresses that are associated with a given Resolver endpoint. With these metrics, you can see at a glance the activity level for inbound and outbound queries going to and coming from your on-premises networks.
Source:: Amazon AWS