ZyWALL 10/50 Internet Security Gateway

5.3.1 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 5.4 to see how to enter the DNS server address(es).

5.3.2 DHCP Configuration

DHCP (Dynamic Host Configuration Protocol, RFC 2131 and RFC 2132) allows individual clients to obtain 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 server 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

Use DNS (Domain Name System) 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 gives 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.

Table 5-1 Example of Network Properties for LAN Servers with Fixed IP Addresses

Choose an IP address

192.168.1.2 - 192.168.1.32; 192.168.1.65 - 192.168.1.254

 

 

Subnet mask

255.255.255.0

 

 

Gateway (or default route)

192.168.1.1 (ZyWALL LAN IP address)

 

 

5.3.3 IP Address and Subnet Mask

Similar to the way houses on a street share a common street name, so too do computers on a LAN share one common network number.

5-2

LAN Setup