[Serusers] why would a client behave differently for nat on outbound as opposed to inbound

[Iqbal]

Couldnt think of a better subject, basically I have a handytone (HT) ,
and a xlite behind the same router, which is natting. SER is external

Now when I call HT to xlite I hear absolutely nothing in either
direction, and nuthing except for a request from xlite hits the
mediaproxy...but when xlite calls HT, mediaproxy lights up like a xmas
tree, and all is well.

What I can see is that if the router is the same one, then surely
something in the HT settings (I have no NAT traversal set in HT) causing
this, or something in xlite telling it what to do, I just cant see what.

Oh xlite/HT to pstn works fine, and inbound from pstn to HT/xlite is also
fine voice both ways.

Iqbal