Because of the different components and processes involved, troubleshooting remote access VPN connections can be a difficult task. This section describes the many tools that are provided with Windows Server 2008 and Windows Vista to troubleshoot remote access VPN connections and the most common problems with remote access VPN connections.
Microsoft provides the following tools to troubleshoot VPN connections from the VPN server:
TCP/IP troubleshooting tools
Authentication and accounting logging
NPS event logging
Network Monitor 3.1
Additionally, Windows Server 2008 and Windows Vista provide the following tools to troubleshoot VPN connections from the VPN client:
TCP/IP troubleshooting ...