Netgear DGB111G Operations Instructions download pdf (Page 175)

Reference Manual for the Model Wireless ADSL Firewall Router DG834G

Network and Routing Basics B-7

202-10006-05, June 2005

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 DG834G wireless router 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

DG834G wireless router 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.

The router accomplishes this address sharing by translating the internal LAN IP addresses to a

single address that is globally unique on the Internet. The internal LAN IP addresses can be either

private addresses or registered addresses. For more information about IP address translation, refer

to RFC 1631, The IP Network Address Translator (NAT).

The following figure illustrates a single IP address operation.

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Netgear DGB111G Operations Instructions Page 175