ZyXEL Communications 2000W Full Cone NAT, Full Cone Restricted Cone Port Restricted Symmetric

Prestige 2000W_V2 User’s Guide

The following table summarizes how these NAT types handle outgoing and incoming packets. Read the following sections for more details and examples.

Table 12

	FULL CONE	RESTRICTED CONE	PORT RESTRICTED	SYMMETRIC
			CONE
Outgoing	The NAT router maps the internal IP address and port of all outgoing			The NAT router maps
Packets	packets to a single IP address and port on the external network.			the internal IP
				address and port of
				each outgoing packet
				to a different external
				IP address and port
				for each different
				destination IP
				address and port.
Incoming	Any external host can	Only external hosts	Only external hosts	A host on the
Packets	send packets to the	with an IP address to	with an IP address	external network can
	external IP address	which the internal	and port to which the	only send packets to
	and port.	host has already sent	internal host has	the specific external
		a packet can send	already sent a packet	IP address and port
		packets to the	can send packets to	that the NAT router
		external IP address	the external IP	used in sending a
		and port.	address and port.	packet to the external
				host’s IP address and
				port.

The examples in these NAT type sections describe NAT translation between internal (private) and external (public) IP addresses.

12.11.2.1 Full Cone NAT

In full cone NAT, the NAT router maps all outgoing packets from an internal IP address and port to a single IP address and port on the external network. The NAT router also maps packets coming to that external IP address and port to the internal IP address and port.

In the following example, the NAT router maps the source address of all packets sent from the Prestige’s internal IP address 1 and port A to IP address 2 and port B on the external network. The NAT router also performs NAT on all incoming packets sent to IP address 2 and port B and sends them to IP address 1, port A.

Chapter 12 User Web Configurator Screens 83