Problem Sharing VPN Connection from Windows after upgrade to 4

At my job, the only way to access the WiFi is via a VPN client run inside Windows. Prior to the upgrade to 4.0, I was able to share the connection with OS X by following instructions I found on this forum (I can no longer find the thread). The basic steps were:

1) Shut down Windows in Parallels and go to Configure. Add new virtual network adapter in Parallels as "Host-only Networking"
2) Run Windows, open VPN connection and click "Properties." Enable in "Advanced" tab the "Internet Connection Sharing" and select Host-only network adapter as "Home networking connection:"
3) In Mac OS X select "System Preferences"->"Network", select "Parallels Host-Guest" network port and press "Advanced..."
4) In "Configure IPv4" select "Manually", set 192.168.0.2 as "IP address", 255.255.255.0 as "Subnet Mask", 192.168.0.1 as "Router" and DNS server IP address as 192.168.0.1 under "DNS Servers". Click "Apply Now"
5) Make sure that you have no "Router" field enabled in any other network port. If you have it then switch the connection to DHCP configuration or the whole the network port to an off state for forcing Mac OS X to use 192.168.0.1 as the default router.
6) Establish VPN connection in Windows.

I believe my other network adapter (the one sharing my WiFi connection to Windows) was set in bridged mode and set to obtain an IP address via DHCP, but I don't remember exactly.

Anyway, after upgrading to 4.0 I lost the ability to do this, and have spent a few hours trying to get it to work again but to no avail. It should also be noted I installed Parallels Internet Security along with my 4.0 install, but I've disabled it until I can get my VPN sharing working again so I can be sure that it's not causing the problem.

Any ideas would be much appreciated.

 

Thank you for the report.
The steps to configure such sharing is described in the KB article http://kb.parallels.com/en/5557 but for now only for the Desktop 3.0. The article will be updated for 4.0

1) please go to the menu Parallels Desktop->Preferences->Networking and disable the DHCP for the Host Only networking. Then please make the DHCP range be 192.168.0.1-192.168.0.254. Apply the settings.

2) please go to the Mac OS X networking setting for the Parallels Host Only Networking Adapter and configure adapter with this settings:
Router: 192.168.0.1
DNS server: 192.168.0.1
Search Domains: leave empty

2) Configure the Windows adapter as described in the http://kb.parallels.com/en/5557

Please make a note here whether this have worked for you

 

After some time passed, I'd want to add some notes to my previous post:

The environment in which Windows Guest connects to some specific server in the network and, in addition to that exposes entry point for the Mac OS X, is hard to configure. The article in the http://kb.parallels.com/en/5557 relates in the first term to the some USB-network device that doesn't have drivers for the Mac OS X.

I can't add any specific detail for your case, but here are some points:
1) VM should have two adapters. One is the Shared or Bridged network connection (if Bridged is workable in your environment). And second adapter is the adapter, connected to configured the specified way HostOnly networking, through which the connection to Mac will be exposed.
2) On the Mac OS X side routing should be configured very specific way: it should route packets from the first VM adapter to the real network card and all other packets to the Parallels Host Only Adapter.

Taking into account all this complications, it is worth to try to find the Mac OS X compatible VPN client..