Why can't I access my folders on the server through the VPN?
I am unable to find my folders on the server even though my VPN tunnel looks like it is working. There is a tunnel established and pinging the server is successful. I am using a wireless network access point to a wired network connected to the Internet through a cable modem. I have Windows XP Professional (upgraded from Windows XP Home Edition) and am using 3Com software. Can you help?
As a rule, users experience problems with browsing the Network Neighborhood or finding shared folders and printers inside a VPN when NetBIOS traffic is not forwarded over the VPN tunnel. Many VPN products can be configured to forward NetBIOS over the tunnel, but some do not, and some VPN administrators choose not to enable NetBIOS relay in their VPN's policies. In addition, some VPN clients run personal firewall software that blocks NetBIOS traffic. For example, it's not uncommon to block NetBIOS on wireless interfaces because NetBIOS broadcasts over wireless are a good way to "leak" company information. Finally, it's possible that your VPN client simply does not know how to find your private network's WINS server if that information is not supplied to your VPN client in its configuration file or during tunnel establishment.
I'm don't know what kind of VPN or personal firewall you are using, so I suggest that you speak with your company's VPN administrator about this problem. They have probably heard the question before and may even have a documented work-around to give you. You can also find a fairly detailed description of tunneling NetBIOS over a Microsoft VPN tunnel here. In the meantime, you may be able to access your folders without being able to browse by directly connecting to them -- for example, enter "net use * IPaddressfoldername" from your Start/Run menu or a command window. Type "net help use" to learn more about this command.
This was first published in February 2005