Some applications, such as VOIP and video, use DIPP source NAT and may require STUN. DIPP NAT uses symmetric NAT, which may have compatibility issues with STUN. To alleviate those issues, persistent NAT for DIPP provides additional support for connectivity with such applications. When you enable persistent NAT for DIPP, the binding of a private source IP address and port to a specific public (translated) source IP address and port persists for subsequent sessions that arrive having that same original source IP address and port.