<P> Most IPv6 networks use autoconfiguration , which requires the last 64 bits of the address for the host . The first 64 bits are the IPv6 prefix . The first 16 bits of the prefix are always 2002 : , the next 32 bits are the IPv4 address , and the last 16 bits of the prefix are available for addressing multiple IPv6 subnets behind the same 6to4 router . Since the IPv6 hosts using autoconfiguration already have determined the unique 64 bit host portion of their address , they must simply wait for a Router Advertisement indicating the first 64 bits of prefix to have a complete IPv6 address . A 6to4 router will know to send an encapsulated packet directly over IPv4 if the first 16 bits are 2002 , using the next 32 as the destination , or otherwise send the packet to a well - known relay server , which has access to native IPv6 . </P>
<P> Most IPv6 networks use autoconfiguration , which requires the last 64 bits of the address for the host . The first 64 bits are the IPv6 prefix . The first 16 bits of the prefix are always 2002 : , the next 32 bits are the IPv4 address , and the last 16 bits of the prefix are available for addressing multiple IPv6 subnets behind the same 6to4 router . Since the IPv6 hosts using autoconfiguration already have determined the unique 64 bit host portion of their address , they must simply wait for a Router Advertisement indicating the first 64 bits of prefix to have a complete IPv6 address . A 6to4 router will know to send an encapsulated packet directly over IPv4 if the first 16 bits are 2002 , using the next 32 as the destination , or otherwise send the packet to a well - known relay server , which has access to native IPv6 . </P>
what is the first 16 bits of an ipv6 6to4 address
what is the first 16 bits of an ipv6 6to4 address
2002 :
2002 :