Editing Martian packet (section)

==Transition mechanisms==
===6to4===
[[6to4]] is an [[IPv6 transition mechanism|IPv6 transition technology]] where the IPv6 address encodes the originating IPv4 address such that every IPv4 {{IPaddr||32}} has a corresponding, unique IPv6 {{IPaddr||48}} prefix.  Because 6to4 relays use the encoded value for determining the end site of the 6to4 tunnel, 6to4 addresses corresponding to IPv4 Martians are not routable and should never appear on the public Internet.

===Teredo tunneling===
[[Teredo tunneling|Teredo]] is another [[IPv6 transition mechanism|IPv6 transition technology]] that encodes the originating IPv4 address in the IPv6 address. However, the [[Teredo tunneling#IPv6 addressing|encoding format]] encodes the Teredo server address and tunnel information before the IPv4 client address.  Thus there is no definable set of prefixes more specific than {{IPaddr|2001:0::|32}} for Teredo packets with Martian end-site addresses. It is, however, possible to spoof Teredo packets with the Teredo server IPv4 address set to a Martian.