Lan Tcp/Ip - ZyXEL Communications P-660RU-Tx User Manual

• 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 P-660RU-Tx supports the IPCP DNS
server extensions through the DNS proxy feature.
If the DHCP is set to Relay, the P-660RU-Tx tells the DHCP clients that it itself is
the DNS server. When a computer sends a DNS query to the P-660RU-Tx, the P-
660RU-Tx acts as a DNS proxy and forwards the query to the real DNS server
learned through IPCP and relays the response back to the computer.
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.

8.3.4 LAN TCP/IP

The P-660RU-Tx has built-in DHCP server capability that assigns IP addresses and
DNS servers to systems that support DHCP client capability.
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.
Where you obtain your network number depends on your particular situation. If
the ISP or your network administrator assigns you a block of registered IP
addresses, follow their instructions in selecting the IP addresses and the subnet
mask.
If the ISP did not explicitly give you an IP network number, then most likely you
have a single user account and the ISP will assign you a dynamic IP address when
the connection is established. If this is the case, it is recommended that you select
a network number from 192.168.0.0 to 192.168.255.0 and you must enable the
Network Address Translation (NAT) feature of the P-660RU-Tx. The Internet
Assigned Number Authority (IANA) reserved this block of addresses specifically for
private use; please do not use any other number unless you are told otherwise.
Let's say you select 192.168.1.0 as the network number; which covers 254
individual addresses, from 192.168.1.1 to 192.168.1.254 (zero and 255 are
reserved). In other words, the first three numbers specify the network number
while the last number identifies an individual computer on that network.
Once you have decided on the network number, pick an IP address that is easy to
remember, for instance, 192.168.1.1, for your P-660RU-Tx, but make sure that no
other device on your network is using that IP address.
The subnet mask specifies the network number portion of an IP address. Your P-
660RU-Tx will compute the subnet mask automatically based on the IP address
P-660RU-Tx User's Guide
Chapter 8 LAN Setup
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