Is it possible to edit a non modifiable value in a custom parameter groups in RDS

I apologize, but it is not possible to edit a non-modifiable parameter like "bind_address" in a custom parameter group for Amazon RDS MySQL, even if you create a new custom parameter group.

In Amazon RDS, parameters are classified as either modifiable or non-modifiable. Non-modifiable parameters are set by the RDS service and cannot be changed by users, even in custom parameter groups. This is done to maintain the stability and security of the database instance.

The "bind_address" parameter is typically considered a critical system parameter that affects how the database server listens for connections. Changing this could potentially impact the way RDS manages connections to your database, which is why it's set as non-modifiable.

If you need to restrict access to your RDS instance, you should consider using other AWS security features instead, such as:

1. Security Groups: You can configure the security group associated with your RDS instance to allow connections only from specific IP addresses or ranges.

2. Network ACLs: If your RDS instance is in a VPC, you can use Network ACLs to control traffic at the subnet level.

3. IAM Database Authentication: For user-level access control, you can enable IAM database authentication for your RDS MySQL instance.

These methods will allow you to restrict access to your RDS instance without needing to modify the non-modifiable "bind_address" parameter.
Sources
Modifying parameters in a DB parameter group in Amazon RDS - Amazon Relational Database Service
Modifying parameters in a DB parameter group in Amazon Aurora - Amazon Aurora

Hello.

As AWS re:Post Agent answers, parameters marked as "non modifiable" in the parameter group cannot be modified by the user.
Basically, I think the easiest way to control access to RDS via network is to change the security group settings.
https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/Overview.RDSSecurityGroups.html