1.2.2 Three ways to acquire WAN's IP address
There are three ways to acquire ESG-103's WAN IP address. The first one is to assign its WAN interface a static valid IP address. Second, users can also acquire ESG-103's WAN IP address by PPPoE and this functionality can help users need not to install PPPoE client software in their own hosts. The last one is to obtain WAN's IP address from DHCP server. Some service provid- ers offer their clients IP addresses by DHCP protocol, and ESG-103 can act as a DHCP client in its 10/100 base-TX WAN side to acquire its WAN IP address. In fact, ESG-103 is an outstanding device, which provides a 10/100 base-TX WAN port.
1.2.3 Act as a DHCP server in its LAN side
ESG-103 can act as a DHCP server in its LAN side, and this functionality can help users need not to configure their own IP addresses. When users are booting their machines, ESG-103 will assign each machine an IP address and other useful information, such as DNS server's IP address etc.
1.2.4 Virtual Server
Users can set up different kinds of servers behind their ESG-103 and remote users in the Internet can access these inside servers by ESG-103's virtual server function.
1.2.5 Firewall via NAT (Network Address Translation)
ESG-103 also plays a role of NAT-type firewall. A NAT-type firewall provides users a secure LAN environment and prevents from being accessed by any anonymous people who desire to do something bad on your network.
1.2.6 Web Management
Users can configure and manage ESG-103 by their own web browsers (IE or Netscape). This means that users wherever they are can manage ESG-103 without any proprietary application installed in their PC.
Chapter 1 Introduction - 2