anchor.diff:         If unspecified, the bind_server_ip value is used.
          Used by: sofia.conf.xml dingaling.conf.xml
     -->
  -  <X-PRE-PROCESS cmd="set" data="external_sip_ip=${{external_ip}}"/>
  +  <X-PRE-PROCESS cmd="set" data="external_sip_ip=$${external_ip}"/>
   
     <!-- unroll-loops
          Used to turn on sip loopback unrolling.
  
positive.code:       affect the sip authentication.  Please review conf/directory/default.xml for more
        information on this topic.
    -->
    <X-PRE-PROCESS cmd="set" data="domain=${{local_ip_v4}}"/>
    <X-PRE-PROCESS cmd="set" data="domain_name=$${domain}"/>
    <X-PRE-PROCESS cmd="set" data="hold_music=local_stream://moh"/>
    <X-PRE-PROCESS cmd="set" data="use_profile=internal"/>
  
negative.code:        If unspecified, the bind_server_ip value is used.
         Used by: sofia.conf.xml dingaling.conf.xml
    -->
    <X-PRE-PROCESS cmd="set" data="external_rtp_ip=$${external_ip}"/>
  
    <!-- external_sip_ip
        Used as the public IP address for SDP.
  