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You can see above an example of how to reference the certificate in MySQL Workbench. Other SQL clients will have a similar configuration option.
Here is an example of connecting to a replica using the standard mysql command line client:
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Here is example output from the above
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Note on “Whitelisted” access restrictions
As part of setup of the Read Replica, certain IP addresses will have been whitelisted. Only traffic originating from these IP addresses will be able to access the Replica. If you are unable to access the replica at all, please keep this in mind as the first thing to check.