ZyXEL Communications VSG1432-B101 Series User Manual

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 Chapter 8 Home Networking
VSG1432-B101 Series User’s Guide
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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”.