title: Obtain public IP from which RDS instance will connect to an external master?
body: <p>To configure RDS MySQL as a slave to an external master (for minimal downtime migrations, as described <a href="http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/MySQL.Procedural.Importing.NonRDSRepl.html" rel="nofollow">here</a>) I need to determine which IP the instance will connect from (to allow traffic from it to my external master).</p>
  
  <p>How can I determine the IP address if the instance isn't publicly accessible? </p>