ZyXEL Communications VSG1435-B101 - V1.10, Manual

Page: 149 / 412

Chapter 8 Home Networking
VSG1435-B101 Series User’s Guide
149
The subnet mask specifies the network number portion of an IP address. Your
ZyXEL Device 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 ZyXEL Device unless you are instructed to do otherwise.
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:
• 10.0.0.0 — 10.255.255.255
• 172.16.0.0 — 172.31.255.255
• 192.168.0.0 — 192.168.255.255
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.
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”.