In my previous article, I have thrown more light on some of the facts that you need to know about networks generally. 

In this article, I will be looking at some of the facts that you should know about Uniform Resource Location also known as URL or web addresses.

The first major issue is to understand how packets reach their proper destination. Even small networks have Computers that could be a potential destination for packets.

IP Addresses and the Internet

The internet also has millions of computers that are spread across the globe. How can you ensure that a packet arrives at its proper destination? this situation is no different from a letter not arriving at its proper destination.

In this article, I will begin by looking at IPv4 IP addresses. This is due to the fact that it is the most common version of an IP address.

An IPv4 address is a series of four three-digit numbers separated by periods. (eg 193.168.1.1).

Each of three-digit numbers must be between  0 and 255. An address 192.168.0.247 would not be a valid one.

The reason for this rule is that these addresses are actually four binary numbers. The computer simply display them to you in decimal format.

Recall that 1 byte is 9 bits. (1s and 0s) and am 8-bit binary number converted to decimal format will be between 0 and 255. A total of 32 bits means that approximately a 4.2billion IP addresses exist.

The IP address of a computer highly informs you about that computer. The first byte or the first computer in that IP address reveals what network class the machine belongs to.

The IP range of 127s is not listed in the above screenshot. The IP address 127.0.0.1 designated to the machine you are in, regardless of the IP address assigned to your machine.

This address is referred to as the ‘loopback address. This address is used to test the machine and the NIC card.

These particular classes are very important as they direct you to the part of the address that represents the network, and to the part that represents the node.

For example, in a Class A address, the first two octets represent the network and the second two octets represent the node.

Finally, in a Class C address, the first three octets represent the network, and the last represents the node. There are also some very specific IP address ranges you should be aware of.

The first, as mentioned previously is 127.0.0.1 or also called the loopback address. It is another way of referring to the network interface card of the machine you are on. private IP addresses are another issue that one should be aware of.

Certain ranges of IP addresses are being designated for use within networks.

These cannot be used as public IP addresses but can be used for internal.

Workstations and servers. Those IP addresses are:

10.0.0.0 to 10.255.255.255
172.16.0.0 to 172.31.255.255
192.169.0.0 to 192.168.255.255

Sometimes, people who are new to networking, have some trouble understanding public and private IP addresses. A good example is an office building.

Without a single office building, each office number must be unique. There can only be one room 101 within that building. This means that it is clear to everyone which room it is.

But there are also other office buildings, many of which have their own office 101. Simply view private IP addresses as office numbers.

Even though the number should be unique, there may be other networks with the Sam IP. Public IP addresses are more like traditional mailing addresses. They must be unique worldwide.

When communicating from office to office, you can use the office number. However, to send a letter to another building, you have to use the complete mailing address.

It is the same type of process that should be followed in networking.

You can communicate within your network using private IP addresses, but to communicate outside of your network must be through a public IP address.

One of the roles of a gateway router is to perform what is called network address translation (NAT), a router takes the private IP address on outgoing packets and replaces it with the public IP address of the gateway router so that the packet can be routed through the internet.

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