Exam 300-820 topic 1 question 131 discussion

STUN is used from the device behind the FW to discover their NAT#ed IP address. So the first 2 options match that. TURN is used only the STUn cannot establish a direct connectivity between the endpoints for media flow.

A.STUN B.STUN C. ICE D. TURN

TURN: An IETF NAT traversal solution designed for a symmetric network. TURN servers are used to assign a port to a client and handle the relay of all packets sent and received. STUN: An IETF NAT traversal solution designed for an asymmetric network. STUN servers are used to assign a port to a client but are not involved with the sending and receiving of packets. ICE: A framework capable of assessing the networked environment a request comes from, and can then act as either a STUN or TURN server on behalf of the client’s needs. ICE is not a NAT traversal protocol in and of itself

wrong! search by RFC A.Clients use this protocol to obtain an IP address and port from a server STUN!!! B.Clients send requests to a server. The server responds with a packet, which contains client public source IP address and port in the payload STUN!! C.Clients try to communicate to diferent candidate transport addresses of other clients to find a path they can use to exchangemedia ICE!!! D. The service is a framework to interconnect clients behind different NAT devices. ICE!!!