An allow list is a security practice that permits access only to resources that have been explicitly approved. This approach is restrictive but effective in reducing the attack surface by blocking anything that is not explicitly allowed. A blocklist, on the other hand, is a practice that specifically denies access to undesirable resources, allowing all others by default. The concept of a sandbox generally refers to a secure, isolated environment where untested or untrusted programs can run without affecting the application in which they run, and traffic filtering is a broad term for the process of allowing or blocking network traffic based on a set of security rules.