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Technical note on subnet masking – Netopia R910 User Manual

Page 178

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B-178 User’s Reference Guide

There are two schemes for distributing the remaining IP addresses:

Manually give each computer an address

Let the Netopia R910 automatically distribute the addresses

These two methods are not mutually exclusive; you can manually issue some of the addresses while the rest
are distributed by the Netopia R910. Using the router in this way allows it to function as an address ser ver.

One reason to use the Netopia R910 as an address ser ver is that it takes less time than manually distributing
the addresses. This is par ticularly true if you have many addresses to distribute. You need to enter information
only once, rather than having to repeatedly enter it on each host separately. This also reduces the potential for
misconfiguring hosts.

Another reason to use the Netopia R910 as an address ser ver is that it will distribute addresses only to hosts
that need to use them.

All Netopia R910s come with an integrated Dynamic Host Control Protocol (DHCP) ser ver. Some routers also
come with a Macintosh Internet Protocol (MacIP) ser ver. These ser vers provide a means of distributing IP
addresses to either a Mac or PC workstation as needed.

When setting up the DHCP or MacIP ser vers in the Netopia R910, it is necessar y to understand how
workstations lease, renew, and release their IP addresses. This information is helpful in determining dynamic
address allocation for a network.

The term “lease” describes the action of a workstation requesting and using an IP address. The address is
dynamic and can be returned to the address pool at a later time.

The term “renew” refers to what the workstations do to keep their leased IP address. At cer tain inter vals, the
workstation talks to the DHCP or MacIP ser ver and renews the lease on that IP address. This renewal allows
the workstation to keep and use the assigned IP address until the next renewal period.

The term “release” refers to a situation where the workstation is no longer using its assigned IP address or has
been shut down. IP addresses can be manually released as well. The IP address goes back into the DHCP or
MacIP address pool to be reassigned to another workstation as needed.

Technical note on subnet masking

Note: The IP address supplied by the Netopia R910 will be a unique number. You may want to replace this
number with a number that your ISP supplies if you are configuring the router for a static IP address. The
automatic IP mask supplied by Smar tStar t is a Class C address. However, the Netopia R910 and all devices on
the same local network must have the same subnet mask. If you require a different class address, you can edit
the IP Mask field to enter the correct address. Refer to the table below.

Number of Devices (other than

Netopia R910) on Local Network

Largest Possible Ethernet Subnet

Mask

1

255.255.255.252

2-5

255.255.255.248

6-13

255.255.255.240

14-29

255.255.255.224