Re: NAT setup

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On Sat, Dec 20, 2003 at 10:07:01AM +0100, Søren Kent Jensen wrote:

> What you need is:
> arp -s <Outside IP> <Outside MAC> pub
> and a route to the <Outside IP> via the internal interface.

And do you know how he can add these two variables dynamically to his
system?

Ramin

> 
> That should do the trick.
> 
> Regards
> Søren Kent Jensen
> 
> 
> ----- Original Message -----
> From: "Ramin Dousti" <ramin@xxxxxxxxxxxxxxxxxxxx>
> To: "Ben Becker" <bbecker2@xxxxxxxxxx>
> Cc: <netfilter@xxxxxxxxxxxxxxxxxxx>
> Sent: Saturday, December 20, 2003 1:30 AM
> Subject: Re: NAT setup
> 
> 
> > Hi Ben,
> >
> > Very interesting concept. There are two major parts to this:
> >
> > 1) Outbound packets from those static IP's to your gateway.
> >    this can be done by enabling proxy-arp on your gateway
> >    to answer to any arp request. This way the clients would
> >    hand over their traffic to your gateway. Subsequently
> >    your gateway would SNAT them and throw it on the Internet.
> >
> > 2) Inbound reply packets coming from the outside. This is a bit
> >    tricky because, once they're in and de-SNATed, your gateway
> >    must know where to send them to.  Since your gateway has only
> >    one default route and no knowledge about those static IP's
> >    behind it, it would automatically send the reply packets back
> >    to the Internet. You might overcome this by blindly forwarding
> >    these ESTABLISHED incoming packets through your internal interface
> >    but you still need to somehow do an ARP for an IP outside your
> >    LAN segment. At this point I don't have any simple solution
> >    for that. But there are some very sharp ARP people here on the
> >    list who could hack something together for you or give you
> >    a pointer to an already hacked solution.
> >
> >
> > Ramin
> >
> >
> > On Fri, Dec 19, 2003 at 05:21:29PM -0500, Ben Becker wrote:
> >
> > > Hello everybody,
> > >
> > > I'm trying to figure out a way to set up basic NAT, but with the ability
> > > to allow users on the local side to use any static IP configuration.
> > > Quick Example: somebody has a static IP configured on their laptop,
> > > stays at a hotel with Internet access, and will be able to browse the
> > > Internet without changing their IP settings.
> > >
> > > My first question is: does anybody know what this feature is called?
> > > Second question: Is it possible to do this with netfilter?  I'm thinking
> > > this would require creating a new virtual interface for each user's
> > > configuration to match their gateway (among other things), but I'm
> > > hoping netfilter has some magical way of doing this (hoping).  If not,
> > > does anybody know of any software that can do this?
> > >
> > > Regards,
> > > Ben Becker
> > >
> >
> >
> 



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