I recent started using a SonicWall NSA2400 and have enabled VPN connecting users with SonicWall’s GVC. Users are able to successfully create the tunnel and ping address on LAN. When try to access local resources either mapped or using \\LAN_Resource\sharename users are either prompted for a username and password or LAN Resource is unable to be located. However, if I attempt to access LAN resource by \\IPADDRESS\sharename resolution works. Further when attempting to start Outlook user is also prompted for U/N and P/W. In some cases username and password are denied. Checking the logs the following errors are present;
Source: LSASRV Category: SPENGO (Negotiator) Event ID: 40961 Description: The Security System could not establish a secured connection with the server cifs/192.168.0.17. No authentication protocol was available.
Source: LSASRV Category: SPENGO (Negotiator) Event ID: 40960 Description: The Security System detected an attempted downgrade attack for server cifs/192.168.0.17. The failure code from authentication protocol Kerberos was "There are currently no logon servers available to service the logon request.