Automatically establishing a connection between phone
and home via the Signpost then becomes relatively straight-
forward. One client, say home, initiates the process by at-
tempting a DNS resolution of phone.alice.signpost.io.
Normal DNS mechanisms cause this query to reach Alice's
Signpost, which has been delegated the zone alice.signpost.
io. The Signpost resolves the name phone by probing and
establishing routes using a bidirectional signalling channel
established between the Signpost and Alice's devices. The
Signpost dynamically probes a variety of channels to deter-
mine whether multiple routes can be established, and create
them if so. The result is that various channels (e.g., VPN,
TOR, etc) are created between Alice's phone and computer,
and at least one valid IP address endpoint returned in the
DNS query if any viable route exists.
Without Signposts, Alice would have had to manually con-
gure a port-forward at her NAT box, or run VPN software
on her phone. Not normally visible to users, the demo incor-
porates a lightweight mechanism to display path existence
and properties.