User-Defined Chains

User-defined chains provide a way to group rules logically. These chains are called from built-in chains as targets. At any point in the chain, you can call a user-defined chain from the same table. When a user-defined chain terminates with no matches, it returns to the next argument in the calling chain.

When creating user-defined chains, names should be lowercase because uppercase is reserved for built-in chains and targets. The name cannot be one of the built-in names or special values.

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