Why Do People Still Use IPv4?

People still use IPv4 because it’s deeply embedded in existing infrastructure. It’s also structurally different from IPv6, meaning transitioning requires significant cost, training, and hardware upgrades. 

Workarounds like Network Address Translation (NAT) have also extended IPv4’s usability, allowing many businesses to face no immediate pressure to switch. The addresses are also actively traded in a global market, so there’s still IPv4 availability—at a cost.

Table of Contents

1. Why Did We Run Out of IPv4 Addresses?
2. IPv4 Is Deeply Embedded Worldwide
3. Moving Beyond IPv4 is Expensive
4. IPv4 Still Works?!
5. You Can Still Get IPv4 Addresses
6. Final Thoughts

1. Why Did We Run Out of IPv4 Addresses?

IPv4 was introduced in 1981 to connect devices using a 32-bit addressing system. The system allowed for approximately 4.3 billion unique addresses, a mind-boggling figure we never thought would be fully utilized. Remember, this was a time of floppy disks and MS-DOS. 

Those who could afford a personal computer would pay $1,500 (the equivalent of $5,200 today) for an IBM 5151 running at a blazing-fast 4.77 MHz. This wasn’t the perfect setting for rapid development in computing and networking. 

Fast-forward 30 years, and most developed nations have broadband in every home. It’s unsurprising why people still use IPv4 since you can still get them in several ways, but RIRs like ARIN certainly can’t hand them out like candy anymore. 

a. The Solution: IPv6

I wouldn’t say we’re a forgetful species, but we devised a solution for the IPv4 shortage: IPv6. This solution beefed up the addressing system to use a 128-bit format, meaning we can deploy many more connected devices.

Sounds familiar?

Regardless of criticism, the road to IPv6 hasn’t been easy. My personal view on IPv6 is simply skepticism. However, businesses face many real challenges if they move to IPv6. That’s the crux of the issue.

2. IPv4 Is Deeply Embedded Worldwide

Thirty years may or may not seem like a long time, depending on what you’re discussing. However, it was enough for IPv4 to become firmly entrenched in the very roots of global networking. While “transition” may sound simple, let’s consider the scale.

Hardware such as routers, switches, firewalls, and more are all involved. On the software side, we have operating systems and network protocols, all designed to operate exclusively with IPv4.

Now, imagine this scenario in your average small—to medium-sized business. Upgrading their systems to IPv6 would require replacing hardware and reconfiguring networks, a daunting and expensive task. 

a. There’s Ubiquity in Networking Standards

We’ve had decades to standardize IPv4 across industries and devices. Everything from enterprise-level networks to consumer electronics defaults to IPv4 by design. This consistency ensures seamless communication, which is critical for businesses and individuals.

The fact that people still use IPv4 creates inertia. Organizations hesitate to disrupt established systems, especially when those systems are functioning adequately. The famous adage “not broken, don’t fix” comes to mind here.

b. It’s Familiar for Tech Professionals

IPv4 has been the default for IT professionals for decades, making it a known and trusted entity. Engineers and administrators are fluent in IPv4 subnetting, address allocation, and troubleshooting methods. 

Switching to IPv6 introduces a learning curve many teams are hesitant to tackle without a pressing need. Again, it’s not broken; don’t fix it.

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3. Moving Beyond IPv4 is Expensive

In any discussion about new technologies, cost is often the biggest elephant in the room. We know people still use IPv4 and that migrating will be expensive, but can you imagine the scope? Let’s break it down into dollars and cents (or sense, if you prefer).

a. Hardware Upgrades

Most legacy network hardware was designed exclusively for IPv4. And if you know businesses, they only upgrade these if the house is on fire. To adopt IPv6, companies often need to replace outdated equipment with IPv6-compatible versions.

A small business with ten branch offices may need to upgrade dozens of routers and switches. The expenses can quickly add up at an average cost of $500–$1,000 per device, not to mention the labor costs for installation and configuration.

b. Software and Application Compatibility

IPv6 introduces a different address structure, requiring software to be updated or replaced to handle the new protocol. Applications that rely on hardcoded IPv4 configurations may need to be rewritten, and some legacy software might lack any support for IPv6.

For example, a financial institution using custom-built software for transaction processing may find that rewriting or updating the application for IPv6 compatibility costs hundreds of thousands of dollars. 

c. Training and Knowledge Gaps

IPv6 fundamentally differs from IPv4, meaning IT teams need training to effectively manage and troubleshoot IPv6 networks. This training requires time, money, and resources that many organizations prefer to allocate elsewhere.

Suppose a company needs to train a team of 10 network engineers in IPv6 addressing, routing, and security. If training costs range from $1,000 to $2,000 per person, it could represent a huge chunk of change for many companies. 

d. Operational Downtime

The transition process to IPv6 can lead to operational disruptions. Most businesses, especially those operating 24/7, fear downtime that could negatively impact customer experience or revenue.

Don’t imagine that the cost of downtime is negligible. For example, operational downtime in eCommerce can be counted in the tens or hundreds of thousands of dollars per minute. Now, how long did that engineer say it would take again?

e. No Immediate Gain from IPv6

For many organizations, the benefits of IPv6—such as a larger address space and improved routing—are not immediately tangible. The return on investment (ROI) for transitioning to IPv6 may take years to materialize, making it less appealing in the short term.

Businesses love the formula: Investment = Exponential Profit. That’s not the case with IPv6. So unless you’re holding a knife at their throats, which business will willingly shift away from IPv4 since it still works?

4. IPv4 Still Works?!

Yeah, IPv4 is exhausted, but not exhausted. That may sound confusing, so let me clarify: IPv4 is exhausted, but clever workarounds have extended its lifespan far beyond initial expectations.

a. Network Address Translation

The private IP addressing allowed by NAT means that devices within a local network can communicate without consuming public IPv4 addresses. Organizations use private IP ranges for internal communication, reserving public addresses only for external-facing services.

For example, a corporate office may run hundreds of computers, printers, and servers on a private IPv4 network (e.g., 10.x.x.x or 192.168.x.x). These devices interact seamlessly without requiring unique public IPv4 addresses.

b. Subnetting: Squeezing More Out of IPv4

Subnetting is another technique that maximizes the efficiency of IPv4 address allocation. Organizations can optimize how addresses are assigned and used by dividing a single IP network into smaller, more manageable sub-networks.

An internet service provider managing thousands of customer connections can divide its IPv4 allocation into subnets, assigning the required IP addresses to each region or customer group. This ensures no address is wasted.

c. IPv4 Reuse Through Dynamic Allocation

Dynamic IP allocation assigns IPv4 addresses to devices only when needed. Once a device disconnects, the IP address is returned to a shared pool for reuse. This method ensures that addresses aren’t tied up unnecessarily.

5. You Can Still Get IPv4 Addresses

People still use IPv4 even though they aren’t available from RIRs. A thriving marketplace has emerged to keep them in circulation. Sources include:

• Leasing Services: Provides temporary access to IPv4 resources without the upfront cost of purchasing.
• Brokers and IP Marketplaces: A regulated way for organizations to acquire additional addresses while ensuring compliance with RIRs.
• Legacy Holders: Older companies sometimes have more addresses than they need and profit by selling their surplus.

6. Final Thoughts

The current attitude of “if it ain’t broke, don’t fix it” is a crucial reason why people still use IPv4. Businesses, ISPs, and consumers prioritize reliability and cost over future-proofing. Until IPv6 offers visible benefits or becomes unavoidable, change comes slowly.

The vibrant IPv4 marketplace also gives businesses a lifeline to extend the protocol’s usefulness. However, it’s a short-term relief that’s no substitute for the scalability and efficiency that IPv6 promises.

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