This doesnt seem to be a dns update issue rather a FS configuration issue. By the way i have paid subscription of dyndns. I tried several combinations of the external_rtp_ip in vars.xml and autonat in the internal profile, and looked at the status of the internal profile. From the combinations that using autonat with either STUN or Host doesnt resolve the ip address. However, if i dont use autonat both Host and STUN do resolve the ip address. So it seems that FS doesnt do an ip lookup whenever autonat is used. Is there a work around for this or what set should i use from the combinations below: ---------------------------------------------------------------- Combinations i tried A. With static ip address and With autonat vars.xml <X-PRE-PROCESS cmd="set" data="external_rtp_ip=49.171.120.82"/> <X-PRE-PROCESS cmd="set" data="external_sip_ip=49.171.120.82"/> internal.xml profile <param name="ext-rtp-ip" value="autonat:$${external_rtp_ip}"/> <param name="ext-sip-ip" value="autonat:$${external_sip_ip}"/> #sofia status profile internal RTP-IP 192.168.10.10 Ext-RTP-IP 49.171.120.82 SIP-IP 192.168.10.10 Ext-SIP-IP 49.171.120.82 URL sip:mod_sofia@192.168.10.10:5060 BIND-URL sip:mod_sofia@192.168.10.10:5060;transport=udp,tcp TLS-URL sip:mod_sofia@192.168.10.10:5061 TLS-BIND-URL sips:mod_sofia@192.168.10.10:5061;transport=tls B. With STUN and With autonat <X-PRE-PROCESS cmd="set" data="external_rtp_ip=stun:stun.freeswitch.org"/> <X-PRE-PROCESS cmd="set" data="external_sip_ip=stun:stun.freeswitch.org"/> <param name="ext-rtp-ip" value="autonat:$${external_rtp_ip}"/> <param name="ext-sip-ip" value="autonat:$${external_sip_ip}"/> #sofia status profile internal RTP-IP 192.168.10.10 Ext-RTP-IP stun:stun.freeswitch.org SIP-IP 192.168.10.10 Ext-SIP-IP stun:stun.freeswitch.org URL sip:mod_sofia@192.168.10.10:5060 BIND-URL sip:mod_sofia@192.168.10.10:5060;transport=udp,tcp TLS-URL sip:mod_sofia@192.168.10.10:5061 TLS-BIND-URL sips:mod_sofia@192.168.10.10:5061;transport=tls C. With STUN and Without autonat <X-PRE-PROCESS cmd="set" data="external_rtp_ip=stun:stun.freeswitch.org"/> <X-PRE-PROCESS cmd="set" data="external_sip_ip=stun:stun.freeswitch.org"/> <param name="ext-rtp-ip" value="$${external_rtp_ip}"/> <param name="ext-sip-ip" value="$${external_sip_ip}"/> #sofia status profile internal RTP-IP 192.168.10.10 Ext-RTP-IP stun:stun.freeswitch.org SIP-IP 192.168.10.10 Ext-SIP-IP 49.171.120.82 URL sip:mod_sofia@49.171.120.82:33758 BIND-URL sip:mod_sofia@49.171.120.82:33758;maddr=192.168.10.10;transport=udp,tcp TLS-URL sip:mod_sofia@49.171.120.82:5061 TLS-BIND-URL sips:mod_sofia@49.171.120.82:5061;maddr=192.168.10.10;transport=tls D. With host and With autonat <X-PRE-PROCESS cmd="set" data="external_rtp_ip=host:myhost.dyndns.org"/> <X-PRE-PROCESS cmd="set" data="external_sip_ip=host:myhost.dyndns.org"/> <param name="ext-rtp-ip" value="autonat:$${external_rtp_ip}"/> <param name="ext-sip-ip" value="autonat:$${external_sip_ip}"/> #sofia status profile internal RTP-IP 192.168.10.10 Ext-RTP-IP host:myhost.dyndns.org SIP-IP 192.168.10.10 Ext-SIP-IP host:myhost.dyndns.org URL sip:mod_sofia@192.168.10.10:5060 BIND-URL sip:mod_sofia@192.168.10.10:5060;transport=udp,tcp TLS-URL sip:mod_sofia@192.168.10.10:5061 TLS-BIND-URL sips:mod_sofia@192.168.10.10:5061;transport=tls E. With host and Without autonat <X-PRE-PROCESS cmd="set" data="external_rtp_ip=host:myhost.dyndns.org"/> <X-PRE-PROCESS cmd="set" data="external_sip_ip=host:myhost.dyndns.org"/> <param name="ext-rtp-ip" value="$${external_rtp_ip}"/> <param name="ext-sip-ip" value="$${external_sip_ip}"/> #sofia status profile internal RTP-IP 192.168.10.10 Ext-RTP-IP host:myhost.dyndns.org SIP-IP 192.168.10.10 Ext-SIP-IP 49.171.120.82 URL sip:mod_sofia@49.171.120.82:5060 BIND-URL sip:mod_sofia@49.171.120.82:5060;maddr=192.168.10.10;transport=udp,tcp TLS-URL sip:mod_sofia@49.171.120.82:5061 TLS-BIND-URL sips:mod_sofia@49.171.120.82:5061;maddr=192.168.10.10;transport=tls