Should I open the port 16379 (bus port) for AWS Elasticache for Redis ?

Question

I have a AWS Elasticache for Redis using the default port 6379. This port is configured in the Security Group attached to the cluster. The engine that I'm using is the 6.2.6

Reading the [following redis documentation](https://redis.io/docs/management/scaling/) it's stated that:

> Every Redis Cluster node requires two open TCP connections: a Redis TCP port used to serve clients, e.g., 6379, and second port known as the cluster bus port. By default, the cluster bus port is set by adding 10000 to the data port (e.g., 16379); however, you can override this in the cluster-port configuration.

The `cluster-port` configuration is a new configuration in Redis 7+, so it's not applicable to my use case.

Should I explicitly open the port `16379` or this _cluster bus port_ is handled by AWS ?

Answer

Good day,

In terms of your question:

>>Should I explicitly open the port 16379 or this cluster bus port is handled by AWS?

AWS ElastiCache for Redis is a managed service, therefore, we try and handle as much as possible for our customers.

In the event you would like to provide access to your ElastiCache Redis cluster, the only requirement on your end is to ensure that the security group attached to the cluster allows port 6379 for resources that would like to access the cluster.

Please take note, opening up the ElastiCache cluster to 0.0.0.0/0, does not expose the cluster to the Internet because it has no public IP address and therefore cannot be accessed from outside the VPC. For additional information, see the article below:

https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/accessing-elasticache.html#authorize-access-vpc

I've also included the article below that provides information on how to connect to the cluster.

https://docs.aws.amazon.com/AmazonElastiCache/latest/red-ug/nodes-connecting.html

Hope this answers your question.

Should I open the port 16379 (bus port) for AWS Elasticache for Redis ?

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