We are trying to setup a SipXECS server to work with a SIP trunking
provider and having issues getting it to work through our firewall (as
is often the case it seems).  The phones and the PBX are behind the
firewall and NAT'd.  Based on what I've seen, openser should be able to
do what we need, but I haven't been able to find any examples which are
similar to what we are doing.

 It seems like we don't need any registration features, but just need
to rewrite SIP packets to translate internal IP's to external... and
then use rtpproxy to handle the audio traffic?  This seems correct in
theory but I have not been able to get openser configured to do it.

 If anyone can provide any tips or example configurations I would be
very appreciative.  We are getting close to the final deadline on
getting this working.  Thanks in advance.


James Peverill