Explanation
An additional vBond is deployed on the Internet and acts as a STUN server for WAN Edge devices with Internet access and redirects them to the private controller IP addresses.
Reference: https://www.cisco.com/c/en/us/td/docs/solutions/CVD/SDWAN/cisco-sdwan-design-guide.html Note: Session Traversal Utilities for NAT (STUN) is a standardized set of methods, including a network protocol, for traversal of network address translator (NAT) gateways in applications of real-time voice, video, messaging, and other interactive communications.