Network address translation (nat), 1 overview, 1 what you can do in this chapter – ZyXEL Communications Prestige P-870HW-51a v2 User Manual
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P-870HW-51a v2 User’s Guide
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C
H A P T E R
8
Network Address Translation
(NAT)
8.1 Overview
This chapter discusses how to configure NAT on the ZyXEL Device.
Network Address Translation (NAT, RFC 1631) is the translation of the IP address
of a host in a packet, for example, the source address of an outgoing packet, used
within one network to a different IP address known within another network.
8.1.1 What You Can Do in this Chapter
• The Port Forwarding screen lets you configure forward incoming service
requests to the server(s) on your local network (
).
• The DMZ Host screen lets you configure a default server (
8.2 What You Need to Know
The following terms and concepts may help as you read through this chapter.
NAT
In the simplest form, NAT changes the source IP address in a packet received from
a subscriber (the inside local address) to another (the inside global address)
before forwarding the packet to the WAN side. When the response comes back,
NAT translates the destination address (the inside global address) back to the
inside local address before forwarding it to the original inside host.
Port Forwarding
A port forwarding set is a list of inside (behind NAT on the LAN) servers, for
example, web or FTP, that you can make visible to the outside world even though