What Do I Do If a VPN Connection Is Interrupted and a Message Is Displayed Indicating That the DPD Times Out?

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 test whether 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 Huawei devices and IP SLA on Cisco devices) on the on-premises gateway device to keep the connection alive.