What does the firewall action "Redirect" do?

The action "Redirect" in a firewall context generally refers to the modification of packets to route them internally through the router instead of sending them out to their destination. This is particularly useful for directing traffic for special handling or processing, such as when implementing captive portals or when performing protocol inspection.

Choosing to redirect a packet to a specified IP means that any incoming packets that meet certain criteria can be sent to another IP address that is not the original destination. This can be effective in scenarios such as network address translation (NAT) or for handling traffic by other services running on the router, such as proxy servers.

The other options refer to different types of redirection that do not capture the broader functionality of firewall actions or may specify incorrect target types or destinations. For instance, redirecting to a port on the router or on a specific host in the network implies a more narrow formatting of the action that may not account for general use cases across a wider range of scenarios. The idea behind redirection, especially in firewall implementations, is aimed at sending packets toward specific processing targets, typically defined by IP addressing, to manage traffic efficiently and effectively.