ZyXEL Communications wireless active fiber router NAT General Screen, Networking NAT General

Chapter 7 NAT

7.3NAT General Screen

The NAT window General tab allows users to configure NAT settings. 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 is changed to a different IP address known within another network.

Each packet has two addresses – a source address and a destination address. For outgoing packets, NAT maps private (local) IP addresses to globally unique ones required for communication with hosts on other networks. It replaces the original IP source address in each packet and then forwards it to the Internet. The FSG1100HN keeps track of the original addresses and port numbers so incoming reply packets can have their original values restored.

Click Networking > NAT > General to open the NAT General screen.

Networking > NAT > General

The following table describes the NAT general labels in this screen.

Networking > NAT > General

LABEL

DESCRIPTION

NAT Setup

Network	Enable or Disable Network Address Translation (NAT). NAT allows
Address	the translation of an Internet protocol address used within one network
Translation	(for example a private IP address used in a local network) to a
	different IP address known within another network (for example a
	public IP address used on the Internet).
NAT	Enable or Disable NAT Loopback. NAT Loopback allows users on the
Loopback	LAN side to access a pubic server located on the LAN side by a public
	IP address or domain name.
SIP ALG	Enable or Disable SIP ALG. SIP Application Level Gateway (ALG)
	allows VoIP calls to pass through NAT by examining and translating IP
	addresses embedded in the data stream. When a VoIP device behind
	the FSG1100HN registers with the SIP register server, the
	FSG1100HN translates the device’s private IP address inside the SIP
	data stream to a public IP address.
RTSP ALG	Enable or Disable RTSP ALG. Application Level Gateway (ALG).
	This is designed to dynamically open pinholes for media streaming.
	When disabled, you are limited to static NAT only.

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FSG1100HN User’s Guide