Take the 2-minute tour ×  I have an application where I want a
device inside a network behind a NAT to make a call to the
public network giving a server its local address, Later, say 10
or 20 minutes later, I'd like the server to be able to contact
the device inside the network.  Is there any protocol generally
supported by firewalls/routers etc. that would direct me to the
local node if I provided its actual current local address?
share|improve this question You're far better off spending the
same (or less) amount of time and energy developing and
implementing an IPv6-based solution, which will allow you to do
the above. –  Jeremy Visser Jul 1 '12 at 0:20 Yes it would be
much better to forget ipv4 but I haven't figured out how to do
that. Devices are ipv6 enabled for the most part but not all
networks. I see T-Mobile is fully ipv6 enabled.
extremetech.com/mobile/… –  user1069528 Jul 1 '12 at 11:28 I
might be best just to wait for ipv6. Good to be a bit ahead of
the curve with a new application anyways. Tha