Private Ip Addresses; Table 1-2. Netmask Formats - NETGEAR RH348 Reference Manual

Reference Guide for the Model RT328 and Model RH348 ISDN Routers
Table 1-2 displays several common netmask values in both the dotted-decimal and the
masklength formats.
Table 1-2. Netmask Formats
Dotted-Decimal
255.0.0.0
255.255.0.0
255.255.255.0
255.255.255.128
255.255.255.192
255.255.255.224
255.255.255.240
255.255.255.248
255.255.255.252
255.255.255.254
255.255.255.254
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.
1-12
Masklength
/8
/16
/24
/25
/26
/27
/28
/29
/30
/31
/32
Introduction