This document specifies the usage of Datagram Transport Layer Security (DTLS) as a transport protocol for Session Traversal Utilities for NAT (STUN). It provides guidance on when and how to use DTLS with the currently standardized STUN usages. It also specifies modifications to the STUN and Traversal Using Relay NAT (TURN) URIs and to the TURN resolution mechanism to facilitate the resolution of STUN and TURN URIs into the IP address and port of STUN and TURN servers supporting DTLS as a transport protocol. This document updates RFCs 5389 and 5928.