What is IPv4 and how does it work?

What is IPv4?

IPv4 stands for Internet Protocol Version 4, this specifies the networking IP address format and scheme used on your LAN (Local Area Network). When we discuss this with people we normally say this is like a computer’s postcode except each address is unique.

How does IPv4 work?

IPv4 consists of a few parts which are: –

• IP Address – Address of the device
• Subnet Mask (SM) – A special number which limits the numbers / blocks checked when transmitting information
• Gateway (GW) – The IP Address of the router / device that links you to other subnets

So looking at the following IP Address settings: –
IP: 192.168.001.021
SM: 255.255.255.0
GW: 192.168.001.254

The above subnet mask informs us that the device only looks at the last block when communicating across the network so anything outside that range is forwarded to the gateway to handle. With that in mind lets break down the IP address to see what each section means, but before we do each block can be from 001 to 254 (255 is a special number).
192.168
The above block(s) at the start shows that this is a special local address that is not routed to the internet. There are other special addresses like this with different subnet masks allowing more addresses but this is the most common.
001
This block dictates the network.
Depending on the size of your business this could be room, floor, building or site. For our example this will be building / site.
021
This block is the devices address, so looking at the whole address this is the 21st device in building 1 on the private network of 192.168

How does Strobe Technologies use IPv4?

We have included this section on the article as it is common place for companies to have either printer specialists or telephone engineers come in and setup their network devices without thinking to ask us what addresses they should use. In the past this has caused issues with addresses not being unique and devices not talking on the network as expected.
We try to follow this pattern: –

• 192.168.001.xxx
• Local.Address.SITE.DEVICE

We have chosen this map / layout as most SMB’s do not have more than 254 devices and enables clients to have multiple sites or offices in different parts of the country enabling them to be linked via VPN or other means. For example you could have an office in Tiverton with thee range of 192.168.001.xxx with another office in Exeter with the range of 192.168.002.xxx.
Within Device section we also have a map which allows us to group devices and manage the network more efficiently, the map we have is: –

• 000 – 010 = Servers
• 100 – 110 = Printers
• 111 – 190 = Available for third party assignments
• 200 – 253 = Network devices like switches, wireless access points
• 254 = Internet router / gateway

With this layout all end user devices will be between 011 and 099 giving each site the possibility of 88 devices which include desktops, laptops, tablets, mobile phones etc