NETGEAR DG632 - ADSL Modem Router, Reference Manual

Page: 97 / 132

Reference Manual for the Model DG632 ADSL Modem Router
Network and Routing Basics B-7
NETGEAR strongly recommends that you configure all hosts on a LAN segment to 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 recognizes which addresses are local and which are remote
Private IP Addresses
If your local network is isolated from the Internet (for example, when using NAT), 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 range. The
DHCP server of the DG632 modem router is preconfigured to automatically assign private
addresses.
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
Table 7-2. Netmask Formats