Softphone behind NAT issue

[VoipSavedMyLife]

Hi again,

I have Asterisk hosted on a server that has a public IP address and there are no firewalls in front of it. I am located behind a NAT server using the X-Lite Softphone. The problem I am having is that I can place calls but I can't receive any, the Softphone doesn't even ring. I've even tried using a STUN server with no luck.

The extension settings are:

[100]
username=100
type=friend
secret=mypassword
record_out=Adhoc
record_in=Adhoc
qualify=yes
port=5060
nat=yes
mailbox=100@device
host=dynamic
dtmfmode=rfc2833
context=from-internal
canreinvite=no
callerid=My Name <100>

The Softphone is sending NAT keep-alives every 60s and according to Asterisk it is reachable:

CLI> sip show peers
Name/username              Host            Dyn Nat ACL Port     Status    
100/100                    201.x.y.z  D   N      39844    OK (254 ms)

Do you know what could be the problem?

Thanks in advance!


-Maurice