What does the log "Delete duplicated CHILD_SA: for the VPN connection" mean?

Zyxel_James

Question: What does the log "Delete duplicated CHILD_SA: for the VPN connection" mean?

Answer: The log entry “Delete duplicated CHILD_SA” does not indicate an error or malfunction on VPN connection. It's more like to be a IPSec VPN operation log.

When the firewall detects that multiple CHILD_SAs are created for the same VPN policy or IKE session (for example, during rekeying, retransmission, or reconnection events), it will automatically remove the duplicated CHILD_SA and keep only the active and valid one. This mechanism is designed to prevent conflicts.

As long as the VPN connection is stable and users do not experience disconnections or performance issues, no action is required and there is no cause for concern.