Hosts and routers in IPv6-enabled networks can handle packets with an IPv4 address using a technique called IPv4-IPv6 coexistence or transition mechanisms.
One such mechanism is called Dual-Stack configuration, in which hosts and routers are capable of supporting both IPv4 and IPv6 protocols simultaneously. Dual-Stack systems have two addresses, one IPv4 and one IPv6, making them capable of communicating with both IPv4 and IPv6 nodes.
Another mechanism is called IPv6 over IPv4 tunneling, in which packets with an IPv4 address are encapsulated within IPv6 packets and tunneled through the IPv6 network. The encapsulated IPv4 packets are carried across the IPv6 network to the destination router, where the tunneling protocol decapsulates the IPv4 packets and forwards them to the final destination.
Network Address Translation (NAT) is another option for handling packets with an IPv4 address in an IPv6-enabled network. NAT allows multiple devices on a private IPv4 network to share a single public IPv4 address by translating their private addresses to the public address when accessing the internet. This technique allows devices with IPv4 addresses to communicate with devices on the IPv6 network and vice versa.
