Specifications
Table Of Contents
- About This Document
- Understanding Networking and IP Addressing
- Introduction to Networking
- Networking using IP
- Niagara Considerations
- Additional Information
- Configuration and Troubleshooting Tools
- Connecting on a LAN
- Connecting with Direct Dial
- Connecting to an ISP
- Using Security Technologies
- Configuration Files Used for Communication
- Glossary
- Index

Niagara Release 2.3
Revised: May 22, 2002 Niagara Networking & Connectivity Guide
Chapter 1 Understanding Networking and IP Addressing
Networking using IP
1–22
In some installations, either the last subnet, or the first and last subnet are
unavailable. Whether these subnets are usable depends on the routing protocols in
use on the network and the IP implementation on the routing devices on the network.
See Figure 1-4 for examples of subnetted networks.
Special IP
Addresses
There are a number of IP addresses (and ranges) that have been reserved for special
use. Table 1-8 provides the addresses and a description of the function they serve.
C
0 (not subnetted) 255.255.255.0 0 254
2 255.255.255.192 4 62
3 255.255.255.224 8 30
4 255.255.255.240 16 14
5 255.255.255.248 32 6
6 255.255.255.252 64 2
Table 1-7 Subnetting for each class.
Class
Number of
Subnet Bits Subnet Mask
Number of
Subnets
Hosts per
Subnet
Table 1-8 Special IP addresses.
Address or
Range Function
Addresses
ending in 0
This is used to indicate the network ID. For example, 192.168.24.0 would
indicate a whole class C network spanning from 192.168.24.1 to
192.168.24.254. Similarly, 125.0.0.0 would indicate an entire class A network
from 125.0.0.1 to 125.255.255.255. Never assign an address ending in 0 as
a host address.
Addresses
ending in 255
An address ending with 255 is a broadcast address. Any data sent to this
address would be picked up by all the machines on the local network. The
address 192.168.24.255 is an example of the broadcast address for the
192.168.24.0 class C network. Similarly, the broadcast address for the class
A network 125.0.0.0 would be 125.255.255.255. Never assign an address
ending in 255 as a host address.
127.0.0.1 This is a logical network used by the local machine to address itself (it is also
called the loopback address). A host can be reached from other hosts by the
assigned IP address (such as 192.168.1.57) but can be reached from itself
using the assigned IP address or the loopback address. The loopback
address should never be assigned as a host address.
224.0.0.0 to
239.255.255.255
These addresses belong to class D and are used for multicasting.
Multicasting is a form of broadcasting in which only participating hosts
receive the broadcast. Never assign an address from this range as a host
address.