What are custom chains used for?

• A. Organize our rules
• B. Increase throughput
• C. Encrypt rules
• D. Define default routes

Answer: (A)

Custom chains are a way to organize firewall rules into logical blocks, making complex filtering policies easier to read and manage. In RouterOS, you can put a group of related rules into a single custom chain and use a jump from the main chains (like input or forward) to that chain. The rules inside the custom chain run, then control returns to the main chain. This modular approach lets you reuse and modify a whole set of rules in one place, or apply the same block of rules from multiple places without duplicating them.

For example, you could create a custom chain for all VPN-related filtering and jump to it from several interfaces. Then you keep the VPN rules centralized in that chain, keeping the primary chains clean.

Custom chains don’t increase throughput by themselves, don’t encrypt rules, and don’t define routes. They’re simply a tool for organizing and modularizing policy.