Redis Object Cache Plugin

Question

I’m configuring ElastiCache for Redis to work with my RDS instance and have enabled both encryption-at-rest and encryption-in-transit.

However, when I set transit encryption mode to "Required", my WordPress plugin Redis Object Cache fails to connect to the ElastiCache cluster. I want to enforce encrypted TCP connections but still maintain plugin functionality.

Could you help identify whether this issue lies with the ElastiCache configuration or the plugin’s compatibility with the required encryption? Any guidance on how to resolve this would be appreciated.

re:Post Agent · Accepted Answer

The issue you're experiencing is likely related to the Redis Object Cache plugin's compatibility with the required encryption settings in ElastiCache for Redis. When you set the transit encryption mode to "Required," all connections to the ElastiCache cluster must use TLS encryption. It appears that the plugin may not be configured to support TLS connections.

To resolve this issue, you'll need to take the following steps:

1. Ensure that your Redis Object Cache plugin version supports TLS connections. Check the plugin documentation or contact the plugin developers to confirm TLS support.

2. If the plugin supports TLS, you may need to update its configuration to enable TLS connections. Look for settings related to SSL or TLS in the plugin's configuration options.

3. If the plugin doesn't support TLS connections, you have a few options:
   a. Look for an alternative Redis caching plugin that supports TLS connections.
   b. Temporarily set the transit encryption mode to "Preferred" instead of "Required." This allows both encrypted and unencrypted connections, which may allow the plugin to function while you work on a long-term solution.
   c. Contact the plugin developers to request TLS support in future versions.

4. If you decide to use the "Preferred" mode temporarily, ensure that you migrate all your clients to use TLS connections before switching back to "Required" mode.

5. When configuring your Redis client (in this case, the WordPress plugin), make sure to enable TLS in the client configuration and that it's using the correct port for TLS connections (usually 6379).

Remember that using the "Preferred" mode is a temporary solution, and it's crucial to implement proper TLS support for all clients connecting to your ElastiCache cluster to maintain security best practices.

If you continue to face issues after confirming TLS support and proper configuration, you may need to review your ElastiCache security group settings to ensure that the necessary ports are open for TLS connections from your WordPress server.  
**Sources**  
[ElastiCache in-transit encryption (TLS) - Amazon ElastiCache](https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/in-transit-encryption.html)  
[Enabling in-transit encryption - Amazon ElastiCache](https://docs.aws.amazon.com/AmazonElastiCache/latest/dg/in-transit-encryption-enable.html)

Redis Object Cache Plugin

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