What is an IP Address

An IP address is essentially an identifier for a device on a network. This identifier allows communication between devices over Layer 3 of the OSI model.

Layer

Name

Description

7

Application

Human interaction with application on the network

6

Presentation

Data in a usable format and often when encryption occurs

5

Session

Maintains connections between devices, controls sports and sessions

4

Transport

Data communication using protocols like UDP and TCP

3

Network

Path which packets will take over the network

2

Data Link

Media access and physical addressing provided with frame generation

1

Physical

Physical path between devices, converts data to digital

An IP address is a string of characters separated by dots (periods (.)) or colons, depending on the version of IP you are using. In IPv4, this will be a string of 4 octets containing numbers from the decimal system. An example of an IPv4 address is:

192.168.0.1

IPv4 (Internet Protocol version 4) was standardized in 1980, and because the creators were not aware of how many devices would eventually be on the public network, or Internet, 40 years later we have started running low on unique IP addresses which may be used for public access.

In 1998, the IETF saw this limitation and the scarcity of unique addresses and created IPv6 (version 6). If you’re wondering what happened to v5, odd numbers are often used as test cases. IPv6 has been available to us for many years, but implementation has been slow. Therefore many companies are using both IPv4 and IPv6.

An IPv6 address consists of a string of hexadecimal characters that is 128 bits long and is also separated by colons. Each group of numbers is 16 bits, or 4 hex characters. An example of an IPv6 address is:

FE80:CD00:0000:0CDE:1258:0000:212E:729C

Types of IP Addresses

Public or Private

Types of IP addresses also depend on the version you’re using. In IPv4, there are two types of IP addresses, public and private. A device with a public IP address can be communicated with by people all over the world over the Internet. A public IP address must be unique, and generally these are leased to people or companies by an ISP (Internet Service Provider).

A private IPv4 address, on the other hand, is generally used within the local network of a company or home network. The addresses within those company or home networks are unique, however they are not unique among the entire world. Meaning if the laptop I’m using at home has the IPv4 address of 192.168.0.10, there may well be a device on another home or business network that is also on 192.168.0.10. However, there cannot be another device on my same network with that IP or communication won’t be possible. IPv6 addresses, though, are different in that there are so many available addresses that each device, no matter where it is, will have a unique address.

Private IPv4 addresses must fall in the following address spaces, though multiple networks may be carved out to form segments or IP ranges within these spaces.

From Address

To Address

10.0.0.0

10.255.255.255

172.16.0.0

172.16.255.255

192.168.0.0

192.168.255.255

Static or Dynamic

Addresses may also be static or dynamic. A static IP address is a permanent address given to a device, whereas a dynamic address may be dealt out automatically to devices on the network for a temporary time. Dynamic addressing is done differently for IPv4 and IPv6 addresses.

Network Portion

Host Portion

Oak

3235

192.168

0.10

The network segment of the address will direct the packet to which router to go to, and then the router will be able to tell the packet which device to go to based on the host portion of the address. This is what allows communication using logical addresses over layer 3.

How to find my IP address

There are multiple ways to find an IP address. Using the CLI (command line interface) you can simply ping a device by its DNS name and it will usually return an IP address.

Ping from CLI

Now we know one of the public addresses google uses to support its website is 172.217.4.206. You could actually copy that into a browser and it should take you to google.com.

Another way to find an IP address is to use the ipconfig (for PCs) or ifconfig (on Mac or Linux) commands.

IP Config

This will give you the IP information for each network adapter (sometimes called a NIC, Network Interface Card) on your device.

You may also find the IP address of your device in multiple ways using the Operating System’s UI (User Interface).

To easily find IP addresses and correlate DHCP and DNS information you may want to use your DDI solution. In Micetro this can be found in multiple ways either in the grid under the IPAM tab or using the Quick Filter functionality.

Micetro Networks