Enter a domain. The test checks whether the website, its name servers and its mail servers publish IPv6 addresses, and tells you exactly what is missing.
The domain you enter is looked up through Cloudflare's public DNS from your browser. Upzilla does not store it.
A visitor on an IPv6 network reaches your site in three steps, and each one has to work over IPv6. First their resolver asks your name servers for the address. Then it needs an AAAA record — the IPv6 counterpart of the A record — for the name they typed. Finally the web server at that address has to answer. This test checks the published records for all of it, and for your mail servers as well.
The essential one. Without it, IPv6 visitors reach you only through their provider's translation gateway.
Checked separately because it is a separate name. A common oversight: IPv6 on example.com but not on www.
Should have IPv6 addresses themselves, so that resolvers on IPv6-only networks can ask them directly.
Nice to have. Mail is delivered server to server and falls back to IPv4 without anyone noticing.
Close to half of all traffic to large sites already arrives over IPv6, led by mobile networks, where many carriers give phones IPv6 addresses only. Those visitors reach an IPv4-only site through a carrier translator (NAT64): an extra hop, shared with thousands of other users, that you cannot see or measure. With an AAAA record the connection is direct, usually a little faster, and the address in your logs belongs to the visitor rather than to a gateway — which matters for rate limiting, abuse handling and geolocation.
New IPv4 addresses are no longer available from the registries and cost real money on the transfer market. Hosting providers increasingly charge for them, and some services are offered on IPv6 only. Being reachable over both protocols is the low-risk position.
If the site is behind a CDN or a reverse proxy such as Cloudflare, IPv6 is usually a switch — the edge speaks IPv6 to visitors and IPv4 to your server. Otherwise: get an IPv6 address from your hosting provider, make the web server listen on it (listen [::]:443 in nginx), open ports 80 and 443 in the IPv6 firewall — it is a separate rule set from IPv4 — and only then publish the AAAA record. Publishing the record before the server answers sends IPv6 visitors to a dead address; browsers fall back to IPv4 after a delay, but the site feels slow for exactly those users. After the change, monitor the site over IPv6 as well as IPv4: the two can fail independently.
It has an AAAA record in DNS and the server at that address answers. Enter the domain above: the first two checks cover the website, with and without www.
The DNS record that maps a name to an IPv6 address, as an A record maps it to an IPv4 address. A site that supports both protocols has both records for the same name.
It is recommended. Most resolvers still have IPv4 and will reach IPv4-only name servers, but a resolver on an IPv6-only network cannot ask them directly.
The record is published but the server is not answering on that address — typically the web server is not listening on IPv6 or the IPv6 firewall is closed. This test reads DNS; it does not connect to the server.
No. They keep using the A record. The two protocols work side by side, and each visitor uses whichever their network supports.
Upzilla monitors your site over the network your visitors use and alerts you when it stops answering. 10 monitors free.