ZyXEL Communications P-2602H User Manual

Page of 465
Chapter 8 LAN Setup
P-2602H(W)(L)-DxA User’s Guide
106
8.1.2  DHCP Setup
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 ZyXEL 
Device as a DHCP server or disable it. When configured as a server, the ZyXEL Device 
provides the TCP/IP configuration for the clients. If you turn DHCP service off, you must 
have another DHCP server on your LAN, or else the computer must be manually configured. 
8.1.2.1  IP Pool Setup
The ZyXEL Device is pre-configured with a pool of IP addresses for the DHCP clients (DHCP 
Pool). See the product specifications in the appendices. Do not assign static IP addresses from 
the DHCP pool to your LAN computers.
8.2  DNS Server Addresses 
DNS (Domain Name System) maps a domain name to its corresponding IP address and vice 
versa. The DNS server is extremely important because without it, you must know the IP 
address of a computer before you can access it. The DNS server addresses you enter when you 
set up DHCP are passed to the client machines along with the assigned IP address and subnet 
mask.
There are two ways that an ISP disseminates the DNS server addresses. 
• The ISP tells you the DNS server addresses, usually in the form of an information sheet, 
when you sign up. If your ISP gives you DNS server addresses, enter them in the DNS 
Server fields in the LAN Setup screen.
• Some ISPs choose to disseminate the DNS server addresses using the DNS server 
extensions of IPCP (IP Control Protocol) after the connection is up. If your ISP did not 
give you explicit DNS servers, chances are the DNS servers are conveyed through IPCP 
negotiation. The ZyXEL Device supports the IPCP DNS server extensions through the 
DNS proxy feature.
The ZyXEL Device acts as a DNS proxy when the Primary and Secondary DNS Server 
fields are left blank in the LAN Setup screen.
Please note that DNS proxy works only when the ISP uses the IPCP DNS server 
extensions. It does not mean you can leave the DNS servers out of the DHCP setup under 
all circumstances. If your ISP gives you explicit DNS servers, make sure that you enter 
their IP addresses in the LAN Setup screen. 
8.3  LAN TCP/IP 
The ZyXEL Device has built-in DHCP server capability that assigns IP addresses and DNS 
servers to systems that support DHCP client capability.