Netmask formats, Private ip addresses, Rivate – NETGEAR PS111W User Manual

Page 95: Ip a, Ddresses

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6 252
7 254
8 255


The next table displays several common netmask values in both the dotted-decimal and the masklength
formats.

Netmask Formats

Dotted-Decimal Masklength

255.0.0.0 /8
255.255.0.0 /16
255.255.255.0 /24
255.255.255.128 /25
255.255.255.192 /26
255.255.255.224 /27
255.255.255.240 /28
255.255.255.248 /29
255.255.255.252 /30
255.255.255.254 /31
255.255.255.255 /32

NETGEAR strongly advises that all hosts on a LAN segment use the same netmask for the following
reasons:

So that hosts recognize local IP broadcast packets

When a device broadcasts to its segment neighbors, it uses a destination address of the local network
address with all ones for the host address. In order for this scheme to work, all devices on the segment must
agree on which bits comprise the host address.

So that a local router or bridge will know which addresses are local and which are remote

Private IP Addresses


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 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

NETGEAR recommends that you choose your private network number from this list.
Regardless of your particular situation, do not create an arbitrary IP address; always follow the
guidelines explained here. For more information about address assignment, refer to RFC 1918, Address
Allocation for Private Internets,
and RFC 2050, Guidelines for Management of IP Address Space .

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