ZyXEL Communications VMG4380-B10A User Manual page 154

Chapter 8 Home Networking
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 Device, 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 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 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
• 172.16.0.0
• 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".
154
— 10.255.255.255
— 172.31.255.255
VMG4380-B10A / VMG4325-B10A User's Guide