IPv4 vs IPv6: Why Your Domain's IP Address Matters

What Is IPv4 vs IPv6?

Your customer opens a browser and types your domain name. What happens next? Their device needs to find your website’s server, and that requires an IP address—a unique number that identifies a computer on the internet. Under the hood, there are two types of IP addresses: IPv4 and IPv6. This article explains the difference and why it matters for your domain.

IPv4 is the original addressing system, born in the 1980s. It uses numbers like —four groups of up to three digits. But with billions of devices, we’ve nearly run out of new IPv4 addresses. That’s like a city that’s full and can’t give out any more street addresses.

IPv6 is the modern solution. Its addresses look like , using a much longer format. This creates an astronomically large pool of addresses, enough for every device on the planet many times over. For your domain, you can give it both an IPv4 and an IPv6 address so visitors can reach you no matter what network they’re on.

Real-World Analogy

Think of IPv4 like license plates on cars that can only be six characters long. Eventually, you run out of combinations. IPv6 expands the plate to twenty characters—suddenly you have more than enough for every vehicle ever made. Your domain can display both plates so any driver can recognize it.

How IPv4 vs IPv6 Works

Layer 1 — In plain English

Here’s the journey: A customer types your domain. Their device asks a DNS server, “Where’s this website?” The server looks up your records. If you only have an IPv4 address listed (called an A record), the server hands back that number. If you also have an IPv6 address (an AAAA record), the server can give the newer number, and modern devices will prefer that route. Think of it like roads to your shop: IPv4 is the old familiar road, and IPv6 is a brand-new highway. The visitor’s car will choose whichever road works best. But if you only build your shop with the old road, some cars that are programmed to take the highway might not find you easily.

Layer 2 — Technical details

Technical Details

▸A record — maps your domain name to an IPv4 address (e.g., )

▸AAAA record — maps your domain name to an IPv6 address (e.g., )

▸IPv6 is 128-bit, written in 8 groups of 4 hex digits separated by colons. Leading zeros and consecutive zero groups can be compressed with .

▸Modern devices use algorithms like Happy Eyeballs to try IPv6 first, then fall back to IPv4 if the connection fails.

▸For email, sending servers check for AAAA records on your mail server hostname. If they find one, they may prefer IPv6, which can affect deliverability.

Why It Matters for Your Business

If your domain only uses IPv4, visitors on IPv6-only networks can experience slow connections or can’t reach you at all. These networks are growing rapidly, especially with mobile carriers and Internet of Things devices. A missed visit can mean a lost sale or a customer who thinks your site is down.

Search engines like Google also favor sites that work over IPv6, so ignoring it can subtly hurt your SEO. Email deliverability can suffer too: some mail providers prioritize IPv6 when possible, and if your sending server has no IPv6 address but the receiving server expects one, your messages might be delayed or marked as spam.

Adopting IPv6 now isn’t just about technology—it’s about being ready for the future. It shows partners and customers that your infrastructure is reliable. It’s a simple step that protects your online presence as the internet evolves.

Common Issues and Warning Signs

You might be running fine on IPv4 today, but here are signs you’re missing IPv6 readiness:

Common Issues

Some customers report your site is slow or doesn’t load, especially on certain mobile providers. This often happens when their network is IPv6-only and your site can’t be reached without a complex translation step.

Your emails to modern mail systems occasionally bounce or get flagged as suspicious. Receiving servers that prefer IPv6 may try your server’s IPv6 address and fail, harming your sender reputation.

A TechSpy scan shows a warning like “IPv6 not configured” or “missing AAAA record.” That’s your signal that you’re not ready for networks that move to IPv6.

How to Fix or Improve IPv6 Support

Getting IPv6 working is usually a quick addition to your DNS. You just need to know your server’s IPv6 address and have access to your DNS settings.

1Verify your hosting provider or email service supports IPv6. Most modern platforms (like Google Workspace, Microsoft 365, and major CDNs) do. If not, you may need to upgrade or contact them.

2Obtain the correct IPv6 address for your website (and your mail server, if separate). This is typically available in your hosting control panel or from your IT team.

3Log in to your domain’s DNS management panel.

4Add a new AAAA record for your root domain (usually using as the hostname) pointing to that IPv6 address.

5If you send email from your domain, also add an AAAA record for your mail server hostname (like ).

6If your DNS is managed by someone else, forward this article to them along with the IPv6 address they need to add. Simply ask, “Can you enable IPv6 for our domain so we stay accessible on all networks?”

After making changes, run a fresh TechSpy scan to confirm everything is working. Small tweak, big long-term benefit.