Administrator’s Guide for Yealink Video Conferencing Systems843. Click Confirm to accept the change.To configure Static NAT for SIP IP call via web user interface:1. Click on Account->SIP IP Call.2. Select StaticNat from the pull-down list of NAT Traversal.3. Click Confirm to accept the change.To configure static NAT via the remote control:1. Select Menu->Advanced (default password: 0000) ->NAT/Firewall.2. Select the desired value from the pull-down list of Type.3. Configure the NAT public address in the Public IP Address field if Manual Settings isselected from the pull-down list of Type.4. Press the Save soft key to accept the change.To configure static NAT for SIP IP call via the remote control:1. Select Menu->Advanced (default password: 0000) ->SIP IP Call.2. Select StaticNat from the pull-down list of NAT Traversal.3. Press the Save soft key to accept the change.STUNSTUN is a network protocol, used in NAT traversal for applications of real-time voice, video,messaging, and other interactive IP communications. The STUN protocol allows entities behinda NAT to first discover the presence of a NAT and the type of NAT (for more information on theNAT types, refer to NAT Types on page 88.) and to obtain the mapped (public) IP address andport number that the NAT has allocated for the UDP connections to remote parties. Theprotocol requires assistance from a third-party network server (STUN server) usually located onpublic Internet. The IP phone can be configured to work as a STUN client, to send exploratorySTUN messages to the STUN server. The STUN server uses those messages to determine thepublic IP address and