What Do I Do If a VPN Connection Is Interrupted and a Message Indicating DPD Timeout Is Displayed?

This happens because there is no data exchange over the VPN connection. When the SA lifetime ends, the VPN connection is deleted as the peer end does not respond to the dead peer detection (DPD).

Solution

1. Enable DPD on the on-premises gateway device, and verify that data flows from both ends can trigger connection establishment.
2. Deploy a ping shell script on the servers at both ends. Alternatively, configure a keepalive function (for example, NQA) on the on-premises gateway device to keep the connection alive.