You have an on-premises network and an Azure virtual network. You establish a Site-to-Site VPN connection from the on-premises network to the Azure virtual network, but the connection frequently disco

GatewayDiagnosticLog captures general health and activity for the VPN Gateway but does not provide the granular, tunnel-specific details needed to debug frequent IPsec tunnel disconnections.

RouteDiagnosticLog focuses on routing information and BGP routes, which is less directly relevant for diagnosing frequent disconnections of an established IPsec tunnel.

IKEDiagnosticLog provides details about IKE phase 1 and phase 2 negotiations; while IKE issues can cause tunnel failures, the TunnelDiagnosticLog offers a more comprehensive view of the entire tunnel state for disconnection problems.

The TunnelDiagnosticLog specifically provides information related to the health, state, and events of the IPsec tunnel, including disconnections and rekeying failures, which is crucial for troubleshooting VPN tunnel stability issues.