The default Network Access Control List (NACL) behavior in AWS is to allow all traffic inbound and outbound for all subnets within a VPC. This means that if you don't explicitly create and associate a custom NACL with a subnet, the default NACL is applied automatically.
For inbound traffic, the default NACL allows all traffic originating from the internet or other VPCs to enter the subnet. For outbound traffic, it allows all traffic originating from the instances within the subnet to leave and reach its destination.
It's essential to understand that while the default NACL behavior provides flexibility and simplicity, it also means that there's less control over the flow of traffic in and out of the subnet. If more granular control over network traffic is required, you can create custom NACLs with specific allow and deny rules and associate them with the desired subnets within your VPC.
