Address formats
IPv4 uses 32-bit addresses written as four decimal numbers, such as 192.0.2.1. IPv6 uses 128-bit hexadecimal addresses, such as 2001:db8::1, providing a much larger address space.
NAT and direct addressing
Because public IPv4 space is limited, many networks use NAT so multiple devices share one public address. IPv6 has enough address space for broadly unique addressing, while network firewalls still control incoming connections.
Why both addresses may appear
A dual-stack connection supports IPv4 and IPv6 simultaneously. Applications select the available protocol for each destination, so both addresses can be correct even when one is used more often.
- An IPv6 address does not replace IPv4 everywhere at once.
- Different protocol versions can have different providers or routes.
- Checking both versions helps identify partial connectivity problems.