ZyXEL P-870MH-C1 User Guide - Page 147

Network Address Translation (NAT), 8.1 Overview, 8.1.1 What You Can Do in this What

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CHAPTER 8 Network Address Translation (NAT) 8.1 Overview This chapter discusses how to configure NAT on the 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 (Section 8.3 on page 148). • The Trigger Port screen lets you change the Device's trigger port settings (Section 8.4 on page 151). • The DMZ Host screen lets you configure a default server (Section 8.5 on page 156). • The ALG screen lets you enable SIP ALG on the Device (Section 8.6 on page 156). 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. P-870HN-5xb User's Guide 147

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P-870HN-5xb User’s Guide
147
C
HAPTER
8
Network Address Translation
(NAT)
8.1
Overview
This chapter discusses how to configure NAT on the 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 (
Section 8.3 on page 148
).
• The
Trigger Port
screen lets you change the Device's trigger port settings
(
Section 8.4 on page 151
).
• The
DMZ Host
screen lets you configure a default server (
Section 8.5 on page
156
).
• The
ALG
screen lets you enable SIP ALG on the Device (
Section 8.6 on page
156
).
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.