[asterisk-users] [NAT] * + private IP + locked-down firewalls?

[Gilles]

Hello

	In case Asterisk is used in a private LAN behind a firewall while
allowing remote SIP clients to connect from the Net, we must open
UDP5060 for SIP and a range of UDP ports (as set in rtp.conf) so let
incoming voice packets.

Provided the user doesn't have access to the firewall (eg. corporate
or hotel), and the firewall doesn't allow dynamic port opening through
UPnP or NAT-PMP...

1. Can Asterisk use eg. STUN to open those ports and keep them open
through keep-alive packets?
If not, is there another solution to solve this issue in this context?

2. In case a dynamic solution is available, does Asterisk provide a
tool to monitor that the ports are correctly open, so as to ease
problem-solving in case a customer has a problem and needs to be
helped over the phone?
Knowing that ports on the firewalls are correctly open is one less
area to worry about in case Asterisk doesn't work as planned.

Thank you.