Re: Accessing a host with variable IP addresses / connection types

[Celejar <celejar@gmail.com>]

On Fri, 25 Oct 2019 12:25:27 -0400
Celejar <celejar@gmail.com> wrote:

> On Fri, 25 Oct 2019 09:13:31 -0400
> Greg Wooledge <wooledg@eeg.ccf.org> wrote:
> 
> > On Fri, Oct 25, 2019 at 08:56:19AM -0400, Celejar wrote:
> > > Basically, the home network uses 192.168.0.0/24, as do other LANS I
> > > connect to.
> > 
> > So change your home network.
> 
> I suppose I could, I just didn't feel like doing that just to solve a
> problem that should have a better solution ;)
> 
> It would, of course, have been easier to do that than to code an entire
> new custom framework (but much less fun).
> 
> Celejar

Furthermore, changing the addressing scheme is insufficient to solve
the problem: say the home network uses 10.0.0.0/16, and the VPN is
configured to assign the same address to the laptop that it gets when
it's connected locally. How do hosts on the local network that want
to initiate connections to the laptop know whether to send packets
directly over ethernet, or to forward them via the VPN host? I suppose
I'd need something like ProxyArp, but can you point me to user-friendly,
authoritative documentation for using it on *nix systems? And I'd still
need some mechanism for switching ProxyArp on and off depending on
whether the laptop is connected locally or remotely. And even if I got
it working properly, I'd have a non-standard networking configuration
that will almost certainly come back to bite me as some hard to
diagnose problem down the line ;)

I'm no networking expert - if there's a good solution for all this, do
let me know - but as I mentioned in my first post reviving this thread,
we discussed this for a while back then, and no one had a very good
solution to offer.

Celejar