IPv6 test

The test runs automatically. Each row is one of the checks below with its result and timing; the verdict at the top is one of IPv4 only, dual-stack, IPv6 preferred, dual-stack, IPv4 preferred, IPv6 only or offline.

A fetch from ipv4.checkmyip.com, a hostname with only an A record. Success shows your IPv4 address; failure means you are on an IPv6-only network (NAT64/DNS64), which some mobile carriers run.

A fetch from ipv6.checkmyip.com, a hostname with only an AAAA record. Success shows your IPv6 address and proves the whole path works end to end; failure means no usable IPv6 — the normal result for about half of all connections today.

A fetch from ds.checkmyip.com, which has both records. The family the server sees is the one your browser chose (Happy Eyeballs races both and keeps the faster). IPv4 winning on a connection where IPv6 works is often a sign of a slow or flaky IPv6 path worth reporting to your provider.

Our DNS leak test nameserver is reachable over IPv6, so if a resolver in your DNS leak test result has an IPv6 address, your DNS already travels over IPv6. A resolver list with IPv4 addresses only means DNS still runs over IPv4, which is harmless but worth knowing.

IPv6 routers do not fragment packets; a path that cannot carry a full-size packet simply drops it, so small checks pass and large transfers hang. The test therefore also fetches a larger response over the IPv6-only host; if the small fetch succeeds and the large one times out, you have an MTU problem — usually fixed by setting the router's IPv6 MTU to 1280–1492 or enabling MSS clamping.

Your IPv6 address is shown in full and in its shortest form (runs of zeros collapsed to ::). Unlike IPv4, your device has several: a temporary privacy address that changes daily and is used for outgoing connections (what this page sees), a stable address derived from the interface, and a link-local fe80:: address that never leaves the network. Websites see the temporary one, which is why the address here may differ from the one in your system settings. The first 64 bits (the prefix) identify your network and are assigned by your provider; the IPv4 vs IPv6 guide explains the format.

The score summarizes how ready this connection is for the IPv6-only services that are starting to appear: 10/10 for dual-stack with IPv6 preferred and large packets passing, lower for IPv4-preferred dual stack, an MTU problem or DNS over IPv4 only, and 0/10 for no IPv6 at all. It describes the connection, not your device; the same laptop can score 10 at home and 0 at a hotel.

If the test says IPv4 only, the cause is either the provider, the router or the device, in that order of likelihood.

Log in to the router (see how to find your router's IP address) and look for an IPv6 or WAN IPv6 section. Set it to Automatic or DHCPv6 / prefix delegation, enable IPv6 on the LAN side and save. If the WAN page shows no IPv6 address afterwards, your provider does not deliver it on your line yet — ask them; many enable it on request.

All current systems enable IPv6 by default. Check that it was not switched off: Windows › network adapter properties › Internet Protocol Version 6 ticked; macOS › System Settings › Network › Details › TCP/IP › Configure IPv6: Automatically; Android and iOS have no user switch — if the router hands out IPv6, the phone uses it. After changing anything, reconnect and run this test again.

IPv4 addresses are 32 bits long (about 4.3 billion, long since exhausted), written as four numbers. IPv6 addresses are 128 bits, written as eight hexadecimal groups, and there are enough for every device to have its own public address without the address sharing (NAT) that breaks peer-to-peer connections and port forwarding on IPv4. Both run side by side; a connection with both is dual-stack. Full comparison: IPv4 vs IPv6: what is the difference?.