ZyWALL 10 Internet Security Gateway

Chapter 3

Internet Access

This chapter shows you how to configure the LAN as well as the WAN of your ZyWALL for Internet access.

3.1TCP/IP and DHCP for LAN

The ZyWALL has built-in DHCP server capability that assigns IP addresses and DNS servers to systems that support DHCP client capability.

3.1.1 Factory LAN Defaults

The LAN parameters of the ZyWALL are preset in the factory with the following values:

1.IP address of 192.168.1.1 with subnet mask of 255.255.255.0 (24 bits)

2.DHCP server enabled with 32 client IP addresses starting from 192.168.1.33.

These parameters should work for the majority of installations. If your ISP gives you an explicit DNS server address(es), skip ahead to section 3.2 to see how to enter the DNS server address(es).

3.1.2 DHCP Configuration

DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows the individual clients to obtain the TCP/IP configuration at start-up from a server. You can configure the ZyWALL as a DHCP server or disable it. When configured as a server, the ZyWALL provides the TCP/IP configuration for the clients. If set to None, DHCP service will be disabled and you must have another DHCP sever on your LAN, or else the workstation must be manually configured.

IP Pool Setup

The ZyWALL is pre-configured with a pool of 32 IP addresses starting from 192.168.1.33 to 192.168.1.64. This configuration leaves 31 IP addresses (excluding the ZyWALL itself) in the lower range for other server machines, e.g., server for mail, FTP, telnet, web, etc., that you may have.

DNS Server Address

DNS (Domain Name System) is to map a domain name to its corresponding IP address and vice versa, e.g., the IP address of www.zyxel.com is 204.217.0.2. The DNS server is extremely important because without it, you must know the IP address of a machine before you can access it.

There are two ways that an ISP disseminates the DNS server addresses. The first is for an ISP to tell a customer the DNS server addresses, usually in the form of an information sheet, when you sign up. If your ISP does give you the DNS server addresses, enter them in the DNS Server fields in DHCP Setup. The second is to leave this field blank, i.e., 0.0.0.0 — in this case the ZyWALL acts as a DNS proxy.

Internet Access

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