More room for addresses
IPv4 uses 32-bit addresses, usually shown as four decimal numbers. IPv6 uses 128 bits and hexadecimal notation separated by colons, creating a much larger address space. 192.0.2.10 and 2001:db8::10 are reserved documentation examples. IPv6 allows certain runs of zeros to be shortened, so different-looking strings may represent the same address. Address length is a formatting difference, not evidence that something is wrong.
IPv4 has a finite address pool, and growth in connected networks has put pressure on allocation. IPv6 provides room for continued expansion.
Both versions can coexist
Networks and services have upgraded at different times. Dual-stack operation lets a device use IPv4 and IPv6 alongside each other. A domain can provide addresses for both, and connection software chooses a suitable path according to its implementation and network conditions. Other networks use transition mechanisms. Support at the destination is only one part of the journey; the device, access network and route must also permit the connection.
Why do I have IPv6 without setting it up?
An operating system can configure an address automatically when the access network offers IPv6 and the router supports it. For example, a router advertises a network prefix from which a device forms an address; some networks also use DHCPv6. A different router, a new connection or a network configuration change can make IPv6 appear without manual entry. Its appearance alone does not indicate a fault.
Address scope matters too. A link-local address in device settings serves the local link and does not establish public IPv6 connectivity. A website observing an IPv6 connection describes that particular communication, not the protocol used by every application.
Neither version is always faster
Response time depends on routing, congestion, server placement and connection quality. One version may have a better route to a particular service, while another service behaves differently. A single slow request or failure cannot establish that one protocol is universally better. When comparing observations, use the same destination under similar conditions and look for a repeatable pattern instead of comparing unrelated servers.
When IPv6 is not visible
Your access service, router or device might not enable IPv6, or a particular route or destination might be temporarily unavailable. An application using IPv4 does not prove that the entire network lacks IPv6. Check device and router network status and the service offered by the provider if confirmation matters. Avoid disabling a protocol simply to make an address look shorter; settings should follow your actual connection requirements.
Why can one device have several IPv6 addresses?
An interface can keep relatively stable addresses alongside temporary ones for outgoing connections. Temporary addresses rotate over their lifetimes, while an older address may still support existing connections. This alone does not signal a fault or a network change. Rotation reduces some correlation based on a fixed interface identifier but does not prevent all tracking.