Nested Ip Subnets - Netopia 435 Reference Manual

C-12 Netopia ISDN Router Reference Guide

Nested IP subnets

The example follows these rules:
An IP address must not be used as a static address if it is also
in a range of addresses being distributed by DHCP or MacIP.
A single IP address range is used by all the address-served
clients. These include DHCP, BOOTP, MacIP, and WAN clients,
even though BOOTP and static MacIP clients might not be
considered served.
The address range specified for address-served clients cannot
wrap around from the end of the total available range back to
the beginning. See below for a further explanation and an
example.
The network address issued by an ISP cannot be used as a
host address.
A DHCP example
Suppose, for example, that your ISP gave your network the IP
address 199.1.1.32, and a 4-bit subnet mask. Address 199.1.1.32
is reserved as the network address. Address 199.1.1.47 is
reserved as the broadcast address. This leaves 14 addresses to
allocate, from 199.1.1.33 through 199.1.1.46. If you want to
allocate a sub-block of 10 addresses using DHCP, enter "10" in the
DHCP Setup screen's Number of Addresses to Allocate item. Then,
in the same screen's First Address item, enter the first address in
the sub-block to allocate such that all 10 addresses are within your
original block. You could enter 199.1.1.33, or 199.1.1.37, or any
address between them. Note that if you entered 199.1.1.42 as the
first address, network routing errors would probably result because
you would be using a range with addresses that do not belong to
your network (199.1.1.49, 199.1.1.50, and 199.1.1.51).
Under certain situations, you may wish to create remote subnets
from the limited number of IP addresses issued by your ISP or other
authority. You can do this using connection profiles. These subnets