Re: Apps that try to do net-to-nat

[Antony Stone <Antony@Soft-Solutions.co.uk>]

On Friday 30 January 2004 8:40 pm, John A. Sullivan III wrote:

> On Fri, 2004-01-30 at 15:11, Jago Pearce wrote:
> > I'm behind NAT at work and I need to connect to home, which is also
> > behind NAT.
> >
> > What programs have tried to get past the NAT problem? I heard that mnet,
> > the p2p program uses a ticketing system to pass messages. Any other
> > programs that have attempted to do nat-to-nat and done so successfully?
> > In particular - VoIP?
>
> <snip>
> I'm used to the VPN world so for me the obvious choice is to set up a
> VPN tunnel between home and office.  Hopefully it's not a major concern
> but an added benefit is that your VoIP is encrypted and not subject to
> useful interception.  OpenS/WAN (http://www.openswan.org) should work
> nicely if your are running Linux on your gateway.

But, as a discussion on this list pointed out about a week ago, you can't do 
that if neither of the endpoints which you wish to communicate have publicly 
routable addresses.

I think to specify Jago's requirement slightly more explicitly, he has a 
machine at home, which is SNATted out to the Internet (and therefore cannot 
receive connections in from the Internet), and he has a machine at work which 
is in the same situation - it is SNATted behind a firewall so that the 
machine can connect to the Internet, but the Internet cannot connect to the 
machine.

Therefore the requirement here is to break the security policy of both his 
employer and his home ISP by linking together two machines which have been 
assigned non-routable addresses.

Regards,

Antony.

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