[OLSR-users] LQ, HNA and NAT

Thomas Lopatic (spam-protected)
Wed Feb 9 16:04:36 CET 2005

Hi Stefan,

Even if the NAT router allowed non-SYN packets to add an entry to its 
internal state table (some do this to handle re-starts gracefully), we'd 
still have a problem in case of a gateway change as from the Internet 
host's perspective we'd then have a different IP address and probably 
also a different port number for existing TCP connections or UDP sessions.

The proposed solution for this is gateway tunneling, i.e. establishing a 
tunnel to the gateway of your choice and making the default route point 
to the tunnel.

This used to be a feature in the Linux version way back and I tried to 
mimick this behaviour on a standard Windows installation (i.e. no need 
to install additional drivers) by reverse engineering Microsoft's 
ipinip.sys driver. Unfortunately, Windows 2000 Advanced Server was the 
only platform on which I was able to get this to work. Moreover, the 
tunneling driver is now being phased out by Microsoft.

We're now looking for a cross-platform solution. Maybe some kind of 
integration of olsrd and OpenVPN makes sense. We haven't put much 
thought into this, though.


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