Understanding IP addresses

An IP address is made up of 4 bytes, each byte being made up of eight bits, which can have a value of 1 or 0. This gives possible IP addresses of 0.0.0.0 to 255.255.255.255.

Each IP address is also split into two portions, a network portion, which identifies the network the device is on, and the local or host portion, which identifies a particular device.

The subnet mask defines the position of this split between the network and host portions of the address, which is associated with the address. The subnet mask is also a four byte number. Each bit in the subnet mask that is set to 1 denotes that the corresponding bit in the IP address is part of the network portion.

For example, if we have an IP address of 10.10.2.21 and a subnet mask of 255.255.255.0

Therefore, when we send an IP packet to 10.10.2.21, we are actually sending a packet to device 21 on network 10.10.2.0

In the example above, the network 10.10.2.0 can have 256 host addresses, 0 to 255. However, two of the host addresses, the first and last, on each IP network are reserved. The reserved host address with all bits set to 0 is the network address, and the one with bits set to 1 is the broadcast address.

In our example network of 10.10.2.0

10.10.2.0 is the network address

10.10.2.255 is the broadcast address.

When an IP packet is sent to a networks broadcast address each device on the IP network will receive this packet.

It is this IP network broadcast address, which is used when configuring NetSupport School Tutor to browse on an IP subnet other than its own.