IPv4 vs IPv6: The Complete Guide to How the Two Internet Protocols Differ

• 27 June 2026
• by: Ravi Subramanian
• in: Web hosting
• Tags: IP Address, ipv4 vs ipv6, Networking
• note: no comments

Every device that talks on the internet needs an address. The two systems that hand out those addresses are IPv4 and IPv6, and the differences between them shape almost everything about how the modern internet works, from why your home router uses NAT to why your hosting provider may already be serving your site over a second, longer address you have never seen.

If you have ever wondered how to differentiate IPv4 and IPv6, the short version is this: IPv4 is the older, 32-bit system that gave the internet roughly 4.3 billion addresses, and IPv6 is the newer, 128-bit system built to make address scarcity a permanent non-problem. The rest of this guide unpacks what that actually means, why it matters for your website, and how to read both formats.

This article is part of our complete guide to networking and DNS for hosting, which covers how visitors reach your server end to end.

Key Takeaways
• IPv4 uses 32-bit addresses written in dotted decimal (for example, `192.0.2.1`) and provides about 4.3 billion unique addresses, which the internet has effectively exhausted.
• IPv6 uses 128-bit addresses written in hexadecimal separated by colons (for example, `2001:db8::1`) and provides an astronomically larger pool, enough to end address scarcity for good.
• The biggest practical differences are address space, format, NAT, built-in security, and autoconfiguration.
• IPv4 and IPv6 are not directly compatible; they coexist today through dual-stack networking and transition technologies.
• Most modern websites run on both protocols at once, and your hosting provider typically handles this for you.

What is an IP address, and why are there two versions?

An IP address is a numerical label assigned to every device connected to a network that uses the Internet Protocol. It does two jobs at once: it identifies a device and it provides the location information needed to route traffic to that device. When you type a domain name into a browser, the translates that name into an IP address so your request can find the right server.

There are two versions in active use because the original design, IPv4, was created in the early 1980s when nobody imagined billions of phones, laptops, servers, and smart devices all online at once. IPv6 was developed in the 1990s specifically to solve the problem IPv4 was running into: it was running out of addresses. Both versions still operate side by side today.

What is IPv4 and how does it work?

IPv4 (Internet Protocol version 4) is the fourth revision of the Internet Protocol and the foundation of the internet as most people know it. Its defining characteristic is that it uses 32-bit addresses.

A 32-bit address is written as four numbers separated by dots, a format called dotted decimal notation. Each of the four numbers (called an octet) ranges from 0 to 255, because eight bits can represent 256 values. An example is `192.0.2.1`.

Because the address is 32 bits long, the total number of possible IPv4 addresses is 2 to the power of 32, which is roughly 4.3 billion. That sounded like an enormous number in 1981. In practice, large blocks were reserved for special uses, and global demand outpaced supply. By the 2010s the regional internet registries began running out of fresh IPv4 blocks to allocate. This is known as IPv4 exhaustion, and it is the single biggest reason IPv6 exists.

To stretch the limited supply, the industry leaned heavily on NAT (Network Address Translation), which lets many devices on a private network share a single public IPv4 address. Your home router does this every day. NAT works, but it adds complexity and breaks the internet’s original principle that every device should be directly addressable.

What is IPv6 and how does it work?

IPv6 (Internet Protocol version 6) is the successor protocol designed to replace IPv4 over time. Its defining characteristic is that it uses 128-bit addresses instead of 32-bit ones.

Because an IPv6 address is four times longer in bits, it is written differently: as eight groups of four hexadecimal digits separated by colons. A full example looks like `2001:0db8:0000:0000:0000:ff00:0042:8329`. Hexadecimal is used because it represents long binary strings far more compactly than decimal would.

IPv6 also includes shorthand rules to make these long addresses manageable. Leading zeros in any group can be dropped, and one run of consecutive all-zero groups can be replaced by a double colon (`::`). So the address above compresses to `2001:db8::ff00:42:8329`. You can only use the `::` shortcut once per address, because otherwise it would be ambiguous which groups it represents.

The address space is the headline feature. A 128-bit address allows for 2 to the power of 128 possible addresses, a number with 39 digits. Beyond size, IPv6 was designed with a cleaner, fixed-length header for faster routing, native support for autoconfiguration (devices can self-assign addresses without a DHCP server using a method called SLAAC), and a design that removes the need for NAT entirely.

Here is the thing most comparisons get wrong: the jump from IPv4 to IPv6 is not “a bit more room.” It is an almost incomprehensible leap in scale. IPv6’s 128 bits provide enough addresses to assign many trillions of them to every single person alive on Earth, with a near-limitless surplus left over. That was not an accident or over-engineering; it was the entire point. The designers wanted to make address scarcity a permanent non-problem so the workarounds IPv4 forced on us would never be needed again. The most important of those workarounds is NAT. NAT exists because IPv4 ran out of addresses. IPv6 restores the internet’s original end-to-end design, where every device can hold its own real, globally reachable address instead of hiding behind a shared one. The practical consequence is that IPv6 is not just bigger; it is architecturally simpler and closer to how the internet was always meant to work.

What are the key differences between IPv4 and IPv6?

The two protocols differ across several dimensions. Address length and format are the most visible, but the differences in NAT, security, and autoconfiguration are what change how networks are actually built.

Feature	IPv4	IPv6
Address length	32 bits	128 bits
Address format	Dotted decimal (`192.0.2.1`)	Hexadecimal, colon-separated (`2001:db8::1`)
Address space	~4.3 billion addresses	2^128 (a 39-digit number)
Notation example	`203.0.113.42`	`2001:db8:85a3::8a2e:370:7334`
NAT	Commonly required to conserve addresses	Not needed; end-to-end addressing
Header	Variable length, more complex	Fixed 40-byte header, streamlined
Built-in security (IPsec)	Optional, added separately	Designed as part of the protocol
Address configuration	Manual or DHCP	Supports stateless autoconfiguration (SLAAC)
Broadcast support	Yes	No (replaced by multicast and anycast)

A few of these deserve a closer look:

• Address space and format. This is the core distinction. IPv4’s four-number decimal format is human-friendly but small. IPv6’s hexadecimal format is longer to read but vastly larger in capacity. Understanding how to read an in both formats is the foundation for everything else.
• NAT. Under IPv4, NAT is nearly universal because there are not enough public addresses to go around. Under IPv6, there are enough addresses that NAT becomes unnecessary, simplifying routing and restoring direct connectivity.
• Security (IPsec). IPsec, a framework for encrypting and authenticating IP traffic, was bolted onto IPv4 later. IPv6 was designed with IPsec support as a native part of the specification, though in practice it is enabled by configuration rather than always-on.
• Autoconfiguration. IPv6 devices can generate their own addresses automatically. IPv4 typically relies on a DHCP server to hand out addresses.

Why was IPv6 created in the first place?

IPv6 was created to solve IPv4 address exhaustion. The 4.3 billion addresses that IPv4 can theoretically provide were never going to be enough for a world of smartphones, tablets, laptops, servers, IoT sensors, and connected appliances. The Internet Engineering Task Force saw this coming in the early 1990s and began designing a successor.

The goal was not only more addresses. The designers used the opportunity to simplify the packet header for faster routing, build in autoconfiguration, design for native IPsec, and eliminate the need for NAT. In other words, IPv6 fixes the address shortage and cleans up several rough edges that accumulated as IPv4 was stretched far beyond its original design.

Are IPv4 and IPv6 compatible with each other?

No, IPv4 and IPv6 are not directly compatible. They are different protocols with different address formats, and an IPv6-only device cannot natively talk to an IPv4-only device. This is one of the main reasons the transition has taken so long.

The industry solved this with several coexistence strategies:

• Dual-stack. The most common approach. A device, server, or network runs both IPv4 and IPv6 at the same time and uses whichever the other end supports. Most modern hosting and most websites operate this way.
• Tunneling. IPv6 traffic is wrapped inside IPv4 packets so it can travel across IPv4-only infrastructure, or vice versa.
• Translation. Gateways translate between the two protocols when a direct path is not available.

Dual-stack is the workhorse of the transition. It means you rarely have to choose one or the other; you run both, and clients connect over whichever protocol they prefer.

Do you need IPv6 for your website?

In most cases, you do not have to do anything special to support IPv6, because your hosting provider handles it. The practical reality for a website owner is:

• Visitors connect over both protocols. A growing share of internet users, especially on mobile networks, reach sites over IPv6. If your host supports dual-stack, those users connect over IPv6 automatically while everyone else uses IPv4.
• IPv4 is not going away soon. Because IPv4 is still dominant, you cannot rely on IPv6 alone. Running both via dual-stack is the correct posture, not picking a side.
• DNS ties it together. IPv4 addresses live in `A` records and IPv6 addresses live in `AAAA` records. To be reachable over IPv6, your domain needs an `AAAA` record pointing to an IPv6 address, alongside the `A` record for IPv4. If you want a stable, exclusive address for your service, a can be configured for either protocol.

For the vast majority of site owners, the right move is to choose a host that supports dual-stack and let it manage the addressing. You get the reach of IPv6 without giving up IPv4 compatibility.

How DarazHost handles modern networking

DarazHost provides modern, dual-stack-ready networking out of the box. That means IPv4 with dedicated-IP options for sites that need a stable, exclusive address, plus IPv6 support so your site is reachable on both today’s and tomorrow’s internet. Reliable, well-routed connectivity is part of the hosting rather than an add-on you have to engineer yourself, and our 24/7 support team is available whenever you need help configuring `A` and `AAAA` records or planning an IPv6 rollout. You focus on your site; we keep it reachable on every network that matters.

How do you read and write each address format?

Reading the two formats is straightforward once you know the rules.

IPv4. Four decimal numbers (octets), each from 0 to 255, separated by dots. Each octet represents 8 bits. Example: `198.51.100.27`. There is no compression; you write all four numbers.

IPv6. Eight groups of four hexadecimal digits, separated by colons. Two shorthand rules keep it readable:

1. Drop leading zeros in any group. `2001:0db8:0000:0042` becomes `2001:db8:0:42`.
2. Collapse one run of all-zero groups into a double colon (`::`). `2001:db8:0:0:0:0:0:1` becomes `2001:db8::1`. You may use `::` only once per address.

Put together, a long address like `2001:0db8:0000:0000:0000:0000:0000:0001` compresses cleanly to `2001:db8::1`. If you ever break a network into smaller pieces, the same logic that governs applies to both protocols, though IPv6’s vast space makes subnet planning far more generous.

Frequently asked questions

Is IPv6 faster than IPv4? Not inherently. IPv6 has a simpler, fixed-length header that can make routing more efficient, and it avoids the overhead of NAT, which can help in some scenarios. But real-world speed depends far more on your connection, server, and network path than on which IP protocol is in use. The main benefit of IPv6 is capacity and architecture, not raw speed.

Will IPv4 ever be turned off? Not in the foreseeable future. IPv4 is deeply embedded in the global internet, and the transition is happening gradually through dual-stack rather than a hard cutover. Expect both protocols to coexist for many years.

Can a device use IPv4 and IPv6 at the same time? Yes. This is exactly what dual-stack means. A single device, server, or network can hold both an IPv4 and an IPv6 address simultaneously and use whichever the other end of a connection supports.

Why does IPv6 use hexadecimal instead of decimal? Because IPv6 addresses are 128 bits long, writing them in decimal would be unwieldy. Hexadecimal represents binary far more compactly, so each group of four hex digits cleanly maps to 16 bits, keeping the address as short and readable as possible.

Do I need to do anything to make my website work with IPv6? Usually not, if your hosting provider supports dual-stack. You may need an `AAAA` DNS record pointing to an IPv6 address for full IPv6 reachability, but most providers configure this for you. Check with your host to confirm IPv6 support is enabled.