When you create your Elastic Cache cluster, you have to define a Security Group. A Security group is a set of rules that define what IP addresses are authorised to connect to your cluster.
Should you want to connect to your cache cluster from your local machine, be sure to add a rule to authorise your local IP address to connect to the cluster (beware if you're behind a NATing gateway or a proxy, you need to use your external IP address and not your internal IP address)
Details are available at : http://docs.aws.amazon.com/AmazonElastiCache/latest/UserGuide/GettingStarted.CreateCacheCluster.html
Security Group is explained at : http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_SecurityGroups.html
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