Thank you for your reply. Currently the external_sip_ip and internal_rtp_ip are set to the default stun domain I went into the sip_profiles/external.xml Previous settings: sip_ip = $$(local_ip_v4) rtp_ip = $$(local_ip_v4) changed settings to Public IP sip_ip = 107.1.nnn.nnn rtp_ip = 107.1.nnn.nnn I then did a ReStart of the FS Service so as to ensure that the new values were applied With those new values in place I attempted a call to the outside which failed as before (fast-busy) I then went into the log and did not see where FS made any attempt to send any SIP Header to the SIP Trunk at all. That is a change since before it was sending, but just not the correct info. When I returned the values to their previous settings (ReStart, et al) , the log showed that the SIP Header was indeed sent, just with the wrong info. Just for FYI purposes: This FS Server is running Windows 2012 R2 Also in sofia status I see where the In-House IP is showing and not the Public IP (I don't know if this is correct or not)