ZyXEL Communications 50 User Manual
ZyWALL 50 Internet Security Gateway
5-2
LAN
Setup
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).
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.
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.
common network number.