(Address) Restricted Cone NAT

The restricted cone NAT restricts an external host‘s ability to initiate a packet exchange with the internal client by IP address. The restricted cone NAT method requires that the internal client has already initiated a packet exchange with the external host that passed the protocol and port criteria listed in the access list assigned to the restricted cone NAT configuration. Once the internal client initiates a packet exchange with the external host, that host can initiate a packet exchange for that restricted cone binding using any port or protocol. For the restricted cone NAT method, the external server must be the server the client initiated the exchange with (address restriction) and it must know the external public address of the internal client. The external server can initiate an exchange from any port, using any protocol.

Restricted Cone NAT shows an example of address restricted cone NAT.

Restricted Cone NAT