Hi All, I have an issue whereby my cluster is in a mixed nat and not-nat environment. I would like to manipulate the o= field on a per call basis. In short I would like to achieve the below two scenarios, based on the dialplan Internal offer: Owner/Creator, Session Id (o): root 4267 4267 IN IP4 192.168.1.1 External offer: Owner/Creator, Session Id (o): root 4267 4267 IN IP4 208.73.210.48 I have tried the below, with no success to the origin field. dialplan.xml <action application="bridge" data="{sip_from_uri=sip:${caller_id_number}@208.73.210.48}${lcr_auto_route}"/> vars.xml <X-PRE-PROCESS cmd="set" data="bind_server_ip=208.73.210.48"/> internal.xml <param name="ext-rtp-ip" value="$${local_ip_v4}"/> <param name="ext-sip-ip" value="$${local_ip_v4}"/> external.xml <param name="ext-rtp-ip" value="208.73.210.48"/> <param name="ext-sip-ip" value="208.73.210.48"/> Thanks in advance for any assistance, Chris G