NETGEAR DG814 DSL manual Private IP Addresses, Single IP Address Operation Using NAT

Models: DG814 DSL

1 112
Download 112 pages 60.13 Kb
Page 97
Image 97
Private IP Addresses

Reference Manual for the Model DG814 DSL Modem Internet Gateway

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 Model DG814 gateway is preconfigured to automatically assign private addresses.

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 1597, Address Allocation for Private Internets, and RFC 1466, Guidelines for Management of IP Address Space. The Internet Engineering Task Force (IETF) publishes RFCs on its Web site at www.ietf.org.

Single IP Address Operation Using NAT

In the past, if multiple PCs on a LAN needed to access the Internet simultaneously, you had to obtain a range of IP addresses from the ISP. This type of Internet account is more costly than a single-address account typically used by a single user with a modem, rather than a router. The Model DG814 gateway employs an address-sharing method called Network Address Translation (NAT). This method allows several networked PCs to share an Internet account using only a single IP address, which may be statically or dynamically assigned by your ISP.

Networks and Routing Basics

B-7

Page 97
Image 97
NETGEAR DG814 DSL manual Private IP Addresses, Single IP Address Operation Using NAT