Static and dynamic IP addresses explained

Product Management -

The internet is a complex interconnected web of servers and client devices. Each device needs a way to communicate with one another, much like a person gets given a name at birth to communicate with others. In technology terms, there are a few different naming conventions for systems, including MAC addresses and IP addresses.

With IP addresses, IP stands for internet protocol. The full name is internet protocol address, and this is used to both identify systems and connect directly to them over the internet. Every time you connect to the internet, you will be assigned an IP address, which is a unique combination of numbers. This IP address will remain consistent for a few days or weeks with a broadband connection (unless the router becomes disconnected), or may change each time you disconnect and reconnect over a mobile network.

In this post, we will cover two types of IP address – static and dynamic.

What is an IP address?

As explained above, devices use IP addresses to communicate with each other and facilitate connections. Every device on a network is assigned an IP address so it’s able to communicate with other devices on the network. 

Every website you visit also has its own IP address. However, since remembering all the IP addresses of different websites would be too difficult, websites’ IP addresses are mapped onto unique domain names using the Domain Name System (DNS). When you type a domain name like ‘fasthosts.co.uk’ into your web browser, the system of DNS servers and nameservers will then find the IP address associated with this domain name and return it to your web browser. Now that your browser knows the correct IP address, it can connect to it and load the website you wanted.

Want to learn more about the Domain Name System? Check out our guide to DNS.

What’s the difference between a static IP address and a dynamic IP address?

When a device has a static IP address, this means that its IP address doesn’t change. Dynamic addresses, on the other hand, are assigned by the network when the device connects, and then they change over time.

What is a dynamic IP address?

The most commonly used type of IP address is dynamic. This dynamic IP address is subject to change at any time, but will most commonly change after your broadband or mobile connection disconnects. Your internet service provider (ISP) will have a pool of dynamically allocable IP addresses for every user on their network.

Since your ISP has to purchase licences for each individual IP address, it is more cost-effective to buy a small pool and rotate them between customers. This is accomplished through a combination of Network Address Translation (NAT) and the Dynamic Host Configuration Protocol (DHCP).

Why are dynamic IP addresses used?

Consider this: what if every device on your network had its own IP address? According to Aviva, every UK household in 2020 had 10.3 internet-connected devices on average. Considering that the Office for National Statistics (ONS) reports that there are 19.2 million families in the UK, that equates to just under 200 million internet devices in the UK alone.

There are two versions of IP addresses: IPv4 and IPv6. Most of the internet still uses IPv4 with a maximum IP address capacity of 232, which is equal to 4,294,967,296 (just under 4.3 billion). However, it’s predicted that each person will own 15 internet-connected devices by 2030, totalling 125 billion Internet of Things (IoT) devices. This means that without dynamic IP addresses, NAT, and DHCP, many of these IPv4 devices would be unable to connect to the internet as there aren’t enough IPv4 addresses to go round.

NB: IPv6 has surpassed IPv4. This new IPv6 protocol has a theoretical limit of over 340 undecillion, or 340,282,366,920,938,463,463,374,607,431,768,211,456. More than enough capacity to accommodate our internet-connected devices!

What is a static IP address?

Unlike dynamic IP addresses, static IP addresses are set in stone. Rather than rotating upon reconnection, these static IP addresses are reserved for use by a single system. While this isn’t necessary for most users, having a static IP address is particularly important for servers, where multiple client devices will be attempting to connect via the internet.

If your IP address is constantly rotating, it becomes incredibly challenging to provide an easy means of connection for client devices. By making your IP address static, other client devices will always be able to find your server and make a connection.

Why are static IP addresses necessary?

You may be wondering why is this a problem when we use domain name servers (DNS) to convert uniform resource locator (URL) names into IP addresses? In this Fasthosts Domain Propagation article, we explain how ISPs update their DNS records every 24-72 hours. This means a day or more could go by without the DNS record being updated after your dynamic IP address changes, leaving your users without a way to connect to your servers. As most people do not use specialist DNS resolver services, their reliance on ISP DNS forces you to use a static IP address.

Viewing and modifying your IP settings in Windows

To modify your IP settings in Windows, you need to go to the Network Connections window in settings.

Press the Windows Key + R to open a run window. Then type ncpa.cpl and press Enter on the keyboard.

If you are using Wi-Fi, right-click on Wi-Fi Adapter and then select Properties. If you are using a wired connection, follow the same instructions by right-clicking on Ethernet and selecting Properties.

Now you should see an <Adapter Name> Properties window. Click on Internet Protocol Version 4 (TCP/IPv4) and select Properties.

A window will appear showing configurable settings for your IP address, Subnet Mask, and Default Gateway. Below that, you have DNS options for selecting your Preferred DNS Server and Alternative DNS Server.

By default, Windows automatically assigns your system an IP address using DHCP. To set a manual IP address, click Use the following IP address: in this window.

How to set a static IP address

You may not know what IP address to set in this window. Incorrectly doing this will cause your connection to fail, so double-check by following these instructions:

Open run with the Windows Key + R and type cmd.

In the Command Prompt window, type ipconfig.

We are using Ethernet in this example, and the following message appeared in Command Prompt. You should see something similar to this:

Windows IP Configuration

Ethernet adapter Ethernet 2:

Connection-specific DNS Suffix . :

IPv4 Address: 192.168.1.78

Subnet Mask: 255.255.255.0

Default Gateway: 192.168.1.1

Now we can return to the IP address properties window to edit our configuration.

The Default Gateway is our router. You would only change this when multiple routers are in use and connected, to designate a preferred gateway for your device. For now, type out whatever is displayed under Default Gateway in your Command Prompt in the properties window.

The Subnet Mask is useful for nested internal networks. This always defaults to 255.255.255.0, but can be if you run out of allocatable internet IP addresses. You will notice that clicking on the input box will automatically type out 255.255.255.0. Leave this as-is.

For the IPv4 Address, you must use the first three sections of the Default Gateway, with this example being 192.168.1.*. The asterisk can be any number you like between 2-255 (1 and 0 are already reserved by your router).

Try setting this to 192.168.1.2 and clicking Ok. Your internet connection will reset and attempt to assign the new IP address. If you can load a webpage in your browser, you have successfully set a static IP address.

Static vs dynamic IP addresses: which one should I use?

Usually, the type of IP address you use will depend on your device and the nature of your connection. For example, devices like servers work better with static IP addresses because this makes it easier for other devices to connect. Plus, static IP addresses are often used  in business settings, whereas dynamic IP addresses are much more common in home networks.

Pros and cons of static IP addresses

First, let’s look at the pros and cons of using a static IP address. The benefits can include:

  • Easy DNS management
  • Easier to find and connect to servers
  • Reliable communication between devices
  • Reliable geo-location
  • Easier remote access with a virtual private network (VPN)

There are also some disadvantages to consider, including:

  • More hackable due to the fixed ‘location’ of your device
  • Higher fees charged by ISPs

Pros and cons of dynamic IP addresses

Now let’s look at the advantages of dynamic IP addresses:

  • Very easy to manage because DHCP servers automatically assign and configure IP addresses
  • Can reuse IP addresses
  • Better security due to the changing IP address
  • Lower costs

Of course, there are also some disadvantages to consider:

  • Potential remote connection issues
  • Less reliable geo-location
  • Not as good for hosted services (e.g., website hosting or email servers) because dynamic IP addresses don’t work as well with DNS
  • Potential downtime if your ISP can’t assign you a dynamic IP address

Following protocol with Fasthosts

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If you're looking for a UK-based industry leader to host your business site, call us on 0800 0612 153 or email us at sales@fasthosts.co.uk.