[Asterisk-Users] Problem using SPA-2000 behind NAT

[Patrick Conroy]

Hello all,

I have a new Sipura SPA-2000 that I am trying to configure beind a
NAT.  The SPA is able to register to the asterisk server without a
problem and the SPA can make calls to other extension that are not
behind a NAT.  However, when I try to call the SPA from another
extension, the extension connected to the SPA rings, the user at the
SPA answers, and there is no audio in either direction.  When the
extension connected to the SPA is hung up, asterisk still shows the
sip channel open.  I have tried "rtp debug" from the CLI and it looks
like the RTP packets are being sent to the private IP of the SPA
behind the far-end router (so they obviously aren't making it back to
the SPA).  I can make and take calls behind the same NAT with X-Lite
using the same SIP credentials, so it looks to me like a cofiguration
issue on the SPA.  Does anyone know how to configure the SPA-2000
behind a NAT?  Any help would greatly appreciated.

The relevant entry in my sip.conf:
[2001]
type = friend
secret = 2001
auth = md5
nat = yes
host = dynamic
reinvite = no
canreinvite = no
qualify = 300
dtmfmode = rfc2833
context = agent_connect
callerid = "Demo 1" <2001>
disallow=all
allow=alaw


Thanks,
Patrick