nacl-cheatsheet

- Network Access Control List is commonly known as NACL
- VPCs are automatically given a default NACL which allows all outbound and inbund traffic 
- Each subnet within a VPC must be associated with a NACL
- Subnets can only be associated with a subnet, the subnet will automatically be associated with the default NACL
- NACL has inbound and outbound rules (just like Security Groups )
- Rule can either ALLOW or DENY traffic ( unlike Security Groups which can only allow )
- NACLs are STATELESS (any allowed inbound traffic is also allowed outbound )
- WHen you create a NACLs it will deny traffic by default 
- NACLs contain a numbered list of rules that gets evaluated in order from lowest to highest 
- If you needed to block a single IP address you could via NACLs (Security Groups cannot deny)