I'm running Windows7 x64 (fully patched) and the SonicWall 4.2.6.0305 client (64-bit, claims to support Windows7).

I can login to the VPN and access network resources (eg SSH to a machine that lives behind the VPN). However I cannot seem to be able to access shared filesystems.

Windows is refusing to do discovery on the VPN network. I suspect part of the problem is Windows persistently considers the VPN connection to be a 'public network'. Normally, you can open the network and sharing center and modify this setting, however it does not give me a choice for the VPN. So I did the expedient thing and turned on file sharing for public networks. I also disabled the Windows firewall for good measure. Still no luck.

I can access the server directly by putting \\192.168.1.240 in the taskbar, which brings up the list of shares on the server. However, trying to open any of the shares simply tells me "Windows cannot access \\192.168.1.240\share You do not have permission to access ..."; it never asks for a domain password.

I also tried Windows7 native VPN functionality - it couldn't successfully connect to the VPN at all. I suspect this is because SonicWall is using some obnoxious special/undocumented authentication system; I had similar problems trying to connect on Linux with the normal IPsec tools there.

What magical invocation or control panel option am I missing that will let this work? Are there any reasonable debugging strategies? I'm feeling quite frustrated at Windows tendency to not give me much useful information that might let me understand what it is trying to do and what is going wrong.