What is the result of enabling the DPD feature in an IPsec VPN configuration?

Enabling Dead Peer Detection (DPD) in an IPsec VPN configuration is a critical feature designed to enhance the reliability of the VPN connection. When DPD is enabled, the firewall actively monitors the state of the VPN peer by sending periodic "keep-alive" messages. If the firewall does not receive a response to those messages within a specified timeout period, it determines that the peer is unreachable or "dead."

As a result, DPD facilitates the automatic removal of the corresponding tunnel, which helps ensure that resources are not wasted on inactive connections and allows for quicker recovery and re-establishment of a tunnel when a peer becomes reachable again. This feature is crucial in dynamic environments where peers may become unreachable due to network changes or outages.

Other features, such as allowing the peer to initiate connections, infinitely keeping tunnels open, or securing data packets, do not accurately describe the primary function of DPD. Its dedicated goal is to efficiently manage the peer status and ensure that VPN connections remain robust and responsive.