Ip Address And Subnet Mask; Private Ip Addresses - ZyXEL Communications G-4100 V2 User Manual

G-4100 v2 User's Guide

4.4.1 IP Address and Subnet Mask

Like houses on a street that share a common street name, the 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.
The Internet Assigned Number Authority (IANA) reserved a block of addresses specifically
for private use (refer to
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.
The subnet mask specifies the network number portion of an IP address.

4.4.2 Private IP Addresses

Every machine on the Internet must have a unique address. If your networks are isolated from
the Internet, for example, only between your two branch offices, you can assign any IP
addresses to the hosts without problems. However, the Internet Assigned Numbers Authority
(IANA) has reserved the following three blocks of IP addresses specifically for private
networks:
You can obtain your IP address from the IANA, from an ISP or it can be assigned from a
private network. If you belong to a small organization and your Internet access is through an
ISP, the ISP can provide you with the Internet addresses for your local networks. On the other
hand, if you are part of a much larger organization, you should consult your network
administrator for the appropriate IP addresses.
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.
58
Section 4.4.2 on page
10.0.0.0 — 10.255.255.255
172.16.0.0 — 172.31.255.255
192.168.0.0 — 192.168.255.255
58); please do not use any other number unless
Chapter 4 WAN, LAN and Server Setup