Anyone using uvlan out there?

Steven Haigh netwiz at
Thu Sep 13 21:35:26 UTC 2007

A few weeks ago, I stumbled across uvlan... I first thought WTF, then  
upon researching it a little more, I'm starting to really like the  
idea for replacing a traditional VPN between sites etc.

 From the web site:
uvlan is a User-space Virtual Local Area Network. In other words,  
uvlan peers act as nodes on a network switch. Routing ethernet  
traffic between peers inteligently. Thus allowing for multiple  
networks to share resources and even IP address space. Some may call  
it a VPN (Virtual Private Network) application, but it's much more  
powerful. Differences with traditional VPN technology:

    1. It is peer-to-peer
    2. It doesn't require licensing
    3. It is much simpler
    4. It operates at Layer-2 (Ethernet), VPNs generally operate at  
Layer-3 (IP)
       Layer-2 applications like gaming can't be supported with  
Layer-3 tunneling.

How does it work?
Using the libpcap (winpcap for windows users) library, uvlan listens  
to a specific ethernet device. If a broadcast frame is seen, then it  
is sent off to all the peers so they can add it to their records and  
emit the broadcast on their local network. Once this happens, the  
device (computer, router, gaming console, etc) which sent the  
broadcast will be known by all the peers and remote machines will  
know of the device's existance and how to route traffic to it.

This behaviour is identical to a hardware switch. Only difference is  
- this switch is software and the backplane (the medium that passes  
information between switch ports) is encrypted packets on the internet.

 From my understanding, this software is pretty much acting like a  
bridge, but with endpoints over a routed IP network.

Has anyone actually used this? Thoughts? Criticisms?

Steven Haigh

Email: netwiz at
Phone: (03) 90001 6090 - 0412 935 897

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