Chapter 1 Introduction
1.1 Product Introduction
The ESG-103 is a broadband router, which is to provide home users a secure environment in their private side. It also acts as a Network Address Translation (NAT) device and let home users use private IP addresses to access the Internet from single or multiple global IP addresses. ESG-103 pro- vides home users an environment protected by its NAT-type firewall. Because its WAN side is also an Ethernet interface, which is the same as its LAN interface, you can easily plug it into any access device, such as an ADSL/ Cable modem or router, which provides Ethernet interfaces in the LAN side to run for NAT function.
1.2 Key Features
FTP Server
Telnet Server
Host
LAN
WAN
Internet
ESG-103 ADSL/Cable
Modem
Application Illustration
1.2.1 Being a router between two Ethernet interfaces
The ESG-103 connects one Ethernet interface, which is from ADSL/Cable modem's LAN side as its WAN interface. It provides users in its 10/100 base-TX LAN side which can share a single valid IP address. From this kind of configuration, users do not need to apply for a valid IP address for everyone in its LAN side to access Internet. This function can be enabled or disabled. If users apply for many public IP addresses for some purpose, they are also able to use those IP addresses to connect to the Internet.
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