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1 full cone nat, Table 12 nat types – ZyXEL Communications P2000W User Manual

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P-2000W_V2 User’s Guide

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

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.

Table 12 NAT Types

FULL CONE

RESTRICTED
CONE

PORT
RESTRICTED
CONE

SYMMETRIC

Incoming

Packets

Any external host

can send packets to

the mapped

external IP address

and port.

Only external hosts

with an IP address

to which the internal

host has already

sent a packet can

send packets to the

mapped external IP

address and port.

Only external hosts

with an IP address

and port to which

the internal host

has already sent a

packet can send

packets to the

mapped external IP

address and port.

A host on the external

network can only send

packets to the specific

mapped external IP

address and port that the

NAT router used in

sending a packet to the

external host’s IP address

and port.

Outgoing

Packets

The NAT router maps the internal IP address and port of all

outgoing packets to a single IP address and port on the

external network.

The NAT router maps 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.

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