Ip Address And Subnet Mask; Dns Server Address Assignment - ZyXEL Communications NBG4115 User Manual

Note: Regardless of your particular situation, do not create an arbitrary IP address;
always follow the guidelines above. For more information on address assignment,
please refer to RFC 1597, Address Allocation for Private Internets and RFC 1466,
Guidelines for Management of IP Address Space.

4.5.7 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. 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 NBG4115, 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 NBG4115 will
compute the subnet mask automatically based on the IP address that you entered. You don't need
to change the subnet mask computed by the NBG4115 unless you are instructed to do otherwise.

4.5.8 DNS Server Address Assignment

Use DNS (Domain Name System) to map a domain name to its corresponding IP address and vice
versa, for instance, 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 computer before you can access
it.
The NBG4115 can get the DNS server addresses in the following ways.
The ISP tells you the DNS server addresses, usually in the form of an information sheet, when you
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sign up. If your ISP gives you DNS server addresses, enter them in the DNS Server fields in the
Wizard and/or WAN > Internet Connection screen.
If the ISP did not give you DNS server information, leave the DNS Server fields set to 0.0.0.0 in
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the Wizard screen and/or set to From ISP in the WAN > Internet Connection screen for the
ISP to dynamically assign the DNS server IP addresses.
NBG4115 User's Guide
Chapter 4 Connection Wizard
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