Packet Filtering with Tables
A table is a list of IPv4 and/or IPv6 addresses, much like a list. A table is faster than a list, however, and uses less memory. If you have only a few addresses, using a list is fine, but once you have more than a few, use a table.
Interestingly, you can edit tables without reloading the filter rules, and several programs use this feature to dynamically change how a server behaves. Some people load lists of malware-laden computers into a table to block those hosts, or use external programs to generate such lists. (“You’ve tried to send us four invalid emails in a row? Good-bye!”) Tables can be kept permanently in external files, or you can treat them as ephemera. It’s your choice.
You can create ...