Access control lists
An Access Control List (ACL) is a list of IP addresses or subnets that, in conjunction with VCL code, can be used to verify whether a specific IP address is a member of the list. Unlike edge dictionaries, ACLs support subnet matching and are therefore useful for allowing or blocking ranges of addresses.
ACLs have two parts: an ACL container and the ACL entries within it. Once you attach an ACL container to a version of your service and that service is activated, the data in the container (the ACL entries) becomes "versionless." This means that any updates to the ACL entries will take effect immediately, without requiring a new version of the service.
For more information about using ACLs, see dynamic configuration for Fastly services.