123.123.123.123
(called the dotted form of an IP address).
Within an isolated network, you can assign freely assign IP addresses as long as each one is unique within the network. However, if the network is connected to the &link_internet;, it is required to use registered IP addresses to avoid duplicates.
TCP/IP stores both the sender and the target IP adresses with every packet that is sent over the network. Once the data has arrived at the target, the recipient can see the IP address of the sender and can respond by sending back data to the sender address in a new connection, reversing the operation.
Any IP address has two parts: a network identifier and the identifier of a particular device within that network, the host identifier.
0
, then 7 bits for the
network address, and 24 bits for the host address. As a result, there
can only be 127 class A networks on the Internet.
In dotted form, these addresses break down into
network.local.local.local
.
10
, then 14 bits for the
network address, and 16 bits for the host address.
In dotted form, these addresses break down into
network.network.local.local
.
110
, then
21 bits for the network address, and only 8 bits for the host.
In dotted form, these addresses break down into
network.network.network.local
.
Most importantly, Internet Service Providers (ISPs) will assign
dynamic IPs every time a user connects to the Internet. This
allows the ISP to reuse addresses from its pool of addresses instead
of having to assign each customer a static ID. As a result, your computer's
IP address will vary from time to time every time you connect to the
Internet.