When you research the world of online security and VPNs, you’ve almost certainly come across IPv4 and IPv6. If you’re wondering what is IPv4, it stands for Internet Protocol Version 4 – and it’s a concept that is well worth knowing about.

You’ve definitely encountered IPv4 addresses. They consist of 4 numbers separated by dots, usually with 255 included somewhere. So, a standard IPv4 example could be

Protocols are sets of rules which govern how information passes around the internet. Without them, computers wouldn’t be able to communicate, and data would circulate chaotically, with no way to sort it into different packets of information.

The IPv4 protocol is a specific form designed to identify multiple devices connected to the Web. It’s responsible for generating most IP addresses used on the web, but it’s not exactly cutting edge, having been around since 1983.

How IPv4 works?

Despite the approaching dominance of IPv6, IPv4 addresses remain the most common identifier on the internet. Understanding how they work is a crucial part of network security management.

Learning how IPv4 works isn’t complex. It’s role is to create a road map for each individual packet between two addresses, which could be anywhere in the world. With the right IP address, servers in between can route data efficiently to its destination.

Because of this, the structure of the IP address is crucial. But it’s not the only part of an IPv4 packet. For instance, packets will also include instructions specifying the “time to live” – how long it can bounce around before being neutralized – or flags, which specify that the packet must not be broken up in any way.

If you’re wondering when will IPv4 be phased out, the answer is fairly soon. Estimates range from 5 to 15 years, but the time is approaching when IPv6 is standard.

IPv4 address range

There are five major IPv4 address types: Classes A, B, C, D and E. Classes A-C are the most common for internet connections, and each of them can generate millions of unique addresses.

The IPv4 address range of Class A is 16.7 million hosts spread across 126 separate networks, which we arrive at by using the range between and If you’d like to check your own IP address, finding out where to find IPv4 address is simple. Go to your Network & Internet settings and select the Ethernet option. Your IP address should be right there.

However, internet protocol version 4 has a finite number of addresses. Technically, the internet can support 4,294,967,296 unique IPs (over 4 billion). As we’ll see, that’s not as large a number as you might think.

IPv4 address exhaustion

The problem with IPv4 addresses is that there are only so many. When the protocol was first invented, 4 billion seemed like a enormous figure. But now, it seems like IPv4 address exhaustion is just around the corner.

Regional Internet Registry bodies all report that exhaustion is a real problem. This has led to the emergence of IPv4 brokers, who supply clients requiring bulk IPs. And it has led to urgent calls for the fast-tracking of IPv6.

IPv4 problems

As addresses become harder to come by, it could lead to regular ISP outages and the complete freezing up of internet services as servers and individual users struggle to communicate.

At the moment, we’re living on borrowed time. There are just over 4 billion IPv6 addresses, but the modern world has over 6 billion digital devices. Tech fixes such as NAT routers can only go so far, and might actually postpone the switchover to IPv6.

Moreover, when you use NAT there can be IPv4 issues regarding security. Instead of hosting multiple devices behind one IP, most security experts would prefer a one-on-one solution where they can control their online identity.

Ipv4 no network access

On a more day-to-day basis, IPv4 no network access messages are common. If you get an IPc4 no internet access notification, don’t worry.

Most IPv4 connectivity issues are relatively simple to resolve. Generally, speaking, you can resolve the problem by heading to the Networking tab on Network Connections in Control Panel.

Choose the “Internet Protocol Version 4 (TCP/IPv4)” option, then Properties, and toggle the “Obtain an IP address automatically” and “Obtain DNS server address automatically” options. Hopefully, your IPv4 no internet access issues should then disappear.

If you use a VPN, you might also get a VPN IPv4 connectivity not connected message. In this case, head to the VPN Connection and uncheck the “Use Default Gateway” option under Properties -> Advanced.

IPv4 security issues

The main security issues with IPv6 revolve around IPsec, or the lack of it. IPv6 looks set to be slightly more secure than IPv4 for one reason: it comes bundled with IPSec encryption as standard. This isn’t the case with IPv4 which has no encryption unless it’s added by external means.

Having said that, IPv4 is totally compatible with IPSec, but you’ll need to apply it through a VPN or another tool. Aside from that, IPv4 has few security issues for everyday users.

Limitations of IPv4

The most important IPv4 limitations involve capacity. As we notes earlier, it was a technology designed for the 1980s, when networks were relatively small and limited in scope.

This meant that IPv4 could never be prepared for the rush of global connections represented by the World Wide Web. But additional limitations include a lack of specialist security features and possible conflicts with VPN technologies. Basically the limitations of IPv4 mean that it’s time for a change.

IPv4 firewall protection

If you want to be as secure as possible while relying on IPv4, some form of IPv4 firewall protection is essential. In this context, a Stateful (SPI) Firewall is the best option to go for, as it is configured for network use.

With IPv4 SPI firewall protection, your system can screen packets of data as they arrive, and block unsolicited or malicious data more effectively. It’s not completely watertight, but it does offer an extra layer or protection.

IPv4 is not going to be around forever, but remains a standard for VPN providers. However, as IP address exhaustion bites, it might be best to prepare for IPv6, with a VPN that’s IPv6 compatible, the right virus protection and an IPv6-friendly firewall.