ZyXEL Communications P-2302 User Manual

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Chapter 7 LAN
P-2302HWUDL-P1 Series User’s Guide
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7.1.2  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 DHCP service is disabled, you must have 
another DHCP server on your LAN, or else each computer must be manually configured.
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.
These parameters should work for the majority of installations. If your ISP gives you explicit 
DNS server address(es), read the embedded web configurator help regarding what fields need 
to be configured.
7.1.3  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.
The LAN parameters of the ZyXEL Device are preset in the factory with the following values:
• IP address of 192.168.1.1 with subnet mask of 255.255.255.0 (24 bits)
• 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 explicit 
DNS server address(es), read the embedded web configurator help regarding what fields need 
to be configured.
7.1.4  DNS Server Address
DNS (Domain Name System) is for mapping 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 machine before you can access it.  The DNS server addresses that you enter in 
the DHCP setup 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 first is for an ISP 
to tell a customer the DNS server addresses, usually in the form of an information sheet, when 
s/he signs up.  If your ISP gives you the DNS server addresses, enter them in the DNS Server 
fields in DHCP Setup, otherwise, leave them blank.
Some ISPs choose to pass the DNS servers using the DNS server extensions of PPP 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.
If the Primary and Secondary DNS Server fields in the LAN Setup screen are not specified, 
for instance, left as 0.0.0.0, the ZyXEL Device tells the DHCP clients that it itself is the DNS 
server. When a computer sends a DNS query to the ZyXEL Device, the ZyXEL Device 
forwards the query to the real DNS server learned through IPCP and relays the response back 
to the computer.