IPv4 and IPv6 are two address systems used to identify devices and networks on the internet.
IPv4 uses dotted decimal addresses such as 8.8.8.8. It is still the most familiar format, but the number of available IPv4 addresses is limited. Many providers use NAT, carrier-grade NAT or shared addressing to stretch IPv4 capacity across many users.
IPv6 uses longer hexadecimal addresses such as 2001:db8::1. It provides a much larger address space and can reduce the need for address sharing. A dual-stack connection supports both IPv4 and IPv6, allowing websites and apps to choose the best available path.
DNS uses A records for IPv4 and AAAA records for IPv6. If one family fails while the other works, the issue may be DNS, routing, firewall rules or provider support.
A dual-stack network can reach both IPv4 and IPv6 services. This is useful, but it also means problems can appear only on one address family. A website might load over IPv4 but fail over IPv6 if the AAAA record points to the wrong server, if the firewall blocks IPv6, or if the hosting provider has incomplete IPv6 routing.
When troubleshooting, compare A and AAAA records, test ping or port reachability for both address families, and check which public address your browser is actually using. Some mobile networks and modern ISPs prefer IPv6, while older networks may still depend entirely on IPv4.
A common mistake is adding an AAAA record before the server is actually ready for IPv6 traffic. Browsers may try IPv6 first, and users on IPv6-capable networks can see failures while IPv4-only users think the site is fine. Another mistake is securing IPv4 firewall rules but forgetting that IPv6 has its own firewall path.
VPNs can also change the picture. Some VPNs support IPv4 only, some support both families, and some disable IPv6 to avoid leaks. If your public IPv6 remains visible outside the VPN, websites may still see a network path you did not expect.
Do I need IPv6? Many users can browse with IPv4 only, but IPv6 support is increasingly common and useful for future compatibility.
Why do I only see IPv4? Your ISP, router, VPN or device may not support IPv6, or it may be disabled.
Is IPv6 more private? Not automatically. Privacy depends on configuration, temporary addresses, provider behavior and browser/network settings.
Can a website have both IPv4 and IPv6? Yes. This is called dual-stack and is usually managed with both A and AAAA DNS records.
Should I remove AAAA records if IPv6 is broken? If IPv6 routing or firewalling is broken, removing the AAAA record can be a temporary fix while the server configuration is repaired.