IPv4 and IPv6 for your website: when they matter and what to check before enabling IPv6

Have you spotted an IPv6 option in your hosting service, or noticed that your website behaves differently on mobile data and your home connection? The difference may lie in the network path, rather than the website itself. Before enabling IPv6, understand what you are publishing in DNS and what needs to work at the destination. Adding a record too early can direct visitors to a service that is not ready.

1. IPv4 and IPv6: what changes for your website

IPv4 and IPv6 are two versions of the protocol used to address and carry packets across the internet. IPv4 uses addresses such as 192.0.2.10, while IPv6 uses longer addresses such as 2001:db8::10. These examples are reserved for documentation: they are not addresses to enter in your website configuration.

The practical difference is that visitors can reach the same website through two address families. A dual-stack service accepts both IPv4 and IPv6 connections. You do not need to remove IPv4 to add IPv6.

IPv6 does not automatically make a website faster, more secure or better positioned in search results. The experience depends on the visitor's network, routing and service configuration. Having an IPv6 address assigned to a server does not, by itself, mean that your website responds correctly over it.

When considering a web hosting service, check whether IPv6 is available for your website and which configuration tasks are your responsibility. Infrastructure support and an operational domain configuration are separate matters.

2. What an AAAA record does

DNS associates domain names with the destinations used by different services. For web access, an A record points to an IPv4 address, while an AAAA record points to an IPv6 address. A browser can request both record types and attempt a connection based on the answers and the connectivity available.

Publishing an AAAA record does not enable IPv6 on the server or translate IPv6 traffic into IPv4. It simply announces that the name can be reached at that address. The destination therefore needs to be ready before you change public DNS.

• Check the main domain, its www version and any relevant subdomains separately.
• If a name uses a CNAME alias, check the addresses returned for its target; do not add an AAAA record alongside a CNAME at the same name.
• If you use a CDN or proxy, the published addresses may belong to that service rather than your origin server.

A CDN can accept IPv6 connections from visitors while communicating with the origin over IPv4. The correct setup therefore depends on the endpoint visitors reach. Do not copy an address from another service or assume that every name under your domain uses the same destination.

3. Check the IPv6 path before publishing

Start by confirming that the assigned IPv6 address is correct, stable for the service and routed to the intended destination. Check the service documentation or ask the team responsible for the infrastructure. If you manage the server yourself, this also includes checking its network interface and routes.

1. Confirm that the web service listens on IPv6, not just IPv4.
2. Check firewall rules for both protocols and the access required for HTTP and HTTPS.
3. Review upstream network filters, security rules and restrictions applied before traffic reaches the server.
4. Test from an independent network with working IPv6 connectivity.

A successful ping does not prove that the website works. You need to test the actual web connection. Equally, blocking ICMPv6 indiscriminately can disrupt IPv6, including mechanisms needed to handle packet sizes correctly along the path.

If you use cloud hosting, identify who manages each layer: the network, operating system, firewall and application. A rule allowing IPv4 traffic does not necessarily provide equivalent access over IPv6.

4. Test HTTPS and the website using its real hostname

Before publishing AAAA, test the destination with a tool that can temporarily map the domain to the IPv6 address without changing public DNS. Keep the website's real hostname in the HTTPS request so that site selection and certificate validation remain meaningful.

Opening the IPv6 address directly in a browser is not a sufficient test. It might display a different website configured on the server or produce a certificate error that would not occur when using the domain name.

• The certificate must be valid for the requested hostname and be served with the necessary certificate chain.
• The HTTPS configuration on the IPv6 endpoint must direct the request to the correct website.
• Redirects between HTTP and HTTPS, or between domain variants, must lead to the intended destinations.
• Check pages, images, stylesheets and important website functions together.

A domain certificate is not normally split into an “IPv4 certificate” and an “IPv6 certificate”. However, two endpoints can have different TLS configurations. Also test sign-in, forms and checkout where relevant, taking care not to create unwanted real transactions.

5. Why your website may behave differently across networks

One network may have working IPv6, another may use only IPv4, and a third may have a problematic IPv6 route. Many browsers try to reduce delays by choosing between available connections, but fallback mechanisms do not eliminate every issue. Other applications may behave differently.

To investigate website connectivity, compare requests forced over IPv4 with requests forced over IPv6, using the same hostname and page. Make sure the test network has genuine IPv6 access; otherwise, a failed attempt tells you little about the server.

Check DNS answers, the HTTPS connection, redirects and service logs. If IPv6 reaches a different destination, you might see an older version of the website, a different certificate or inconsistent responses. DNS caching, browser caching and CDN distribution can make comparisons harder.

Record the network used, the time of the test, the requested hostname and the exact error. This information is more useful than a general report that “the website is slow”. Avoid assuming that every difference is caused by IPv6 itself.

6. Publish AAAA carefully and monitor the outcome

Publish the record only after checking connectivity, HTTPS and the application. If you plan to lower the TTL to reduce how long answers remain cached, do so in advance: previously cached answers retain their earlier validity period.

1. Save the existing DNS configuration and record the destination you tested.
2. Add AAAA for the prepared hostname, keeping the A record if you want dual-stack access.
3. Check DNS answers and repeat your tests from different networks.
4. Monitor errors, application behaviour and any differences between the protocols.
5. If problems appear, correct the destination or temporarily remove AAAA; caches mean the effect will not be immediate.

The practical takeaway: enable IPv6 when the entire path to your website is ready, not simply because an option appears in your service settings. Keep IPv4 if you need compatibility with networks that rely on it, and validate each published hostname separately. For clarification about your GazduireOnline.ro service configuration, use the contact page and include your domain, the tests you performed and the errors you observed.