ZyXEL Communications VMG3925-B30C - Network Address Translation (NAT); Overview; What You Can Do in this Chapter; What You Need to Know

VMG3925-B10C/B30C User’s Guide
171
CHAPTER 11
Network Address Translation
(NAT)
11.1 Overview
This chapter discusses how to configure NAT on the VMG. NAT (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.
11.1.1 What You Can Do in this Chapter
• Use the Port Forwarding screen to configure forward incoming service requests to the server(s) on your
local network (Section 11.2 on page 172).
• Use the Applications screen to forward incoming service requests to the server(s) on your local
network (Section 11.3 on page 175).
• Use the Port Triggering screen to add and configure the VMG’s trigger port settings (Section 11.4 on
page 177).
• Use the DMZ screen to configure a default server (Section 11.5 on page 179).
• Use the ALG screen to enable and disable the NAT and SIP (VoIP) ALG in the VMG (Section 11.6 on
page 180).
• Use the Address Mapping screen to configure the VMG's address mapping settings (Section 11.7 on
page 181).
• Use the Sessions screen to configure the VMG's maximum number of NAT sessions (Section 11.7 on
page 181).
11.1.2 What You Need To Know
Inside/Outside
Inside/outside denotes where a host is located relative to the VMG, for example, the computers of your
subscribers are the inside hosts, while the web servers on the Internet are the outside hosts.
Global/Local
Global/local denotes the IP address of a host in a packet as the packet traverses a router, for example,
the local address refers to the IP address of a host when the packet is in the local network, while the
global address refers to the IP address of the host when the same packet is traveling in the WAN side.