Routing NetBIOS with Linux

Introduction

The Microsoft Network Neighborhood relies on an underlying technology called "NetBIOS over TCP/IP" to work. This all works fine on a small LAN, as it relies on network broadcasts, but it can fail over a WAN as many routers cannot forward NetBIOS broadcasts, or they may be performing Network Address Translation which may cause the broadcasts to fail as they contain IP addresses--not only in the header, but in the data.

If you can access a machine on a different, masqueraded network using UNC naming, e.g. \\server, but you cannot see it or any machines in your Network Neighborhood, then chances are the NetBIOS broadcasts necessary for Network Neighborhood to work are not crossing the networks.

It's possible to configure a Linux machine to do NetBIOS forwarding, which will enable us to get the Network Neighborhood working across masqueraded networks. Here's how...