http://blogs.technet.com/brad_rutkowski/archive/2008/04/03/got-ipsec-got-problems-new-tool-released-to-help-you-triage-ipsec-failures.aspxThe Microsoft IPsec Diagnostic Tool is available for Windows Server 2008, for Windows Vista, for Windows Server 2003, and for Windows XP This should help you out when you have those weird "network" issues going on with some clients where IPSECenCommunityServer 2.1 SP1 (Build: 61025.2)