Many real-time communication applications, like VoIP and video conferencing, rely on Session Traversal Utilities for NAT (STUN) to establish and maintain stable connections. However, when these applications are deployed with Dynamic IP and Port (DIPP) source NAT, they can experience connectivity issues. This happens because DIPP uses a symmetric NAT approach, which can change the translated IP address and port for each new session. This frequent change can cause compatibility problems with STUN, often resulting in dropped calls or one-way audio for users.

Persistent NAT for DIPP solves this problem by ensuring a consistent and predictable translation for a given internal source IP and port. When you enable this feature, the mapping between a private source IP address and port and its public translated address and port persists for subsequent sessions. This stable binding is crucial for maintaining seamless, uninterrupted communication, providing the reliable connectivity that real-time applications demand.