ipv4 and ipv6?

[DeathProxy]

Companies that are IPv6 ready are also IPv4 ready. That means that they can cater to people with IPv6 AND people with IPv4.
However, if the company only has an IPv6 address and no IPv4 address, they won't be able to serve people that are only using IPv4, but they will be able to serve people with IPv6 and vice versa.

[perennate]

Yeah, IPv6 is not backwards compatible; the addresses are a different length and there's some other changes in the protocol I think.

[aatish910]

There is IPv4 in IPv6 capsulation as well for those with only IPv6 access.

[perennate]

Well you can use something like http://en.wikipedia.org/wiki/6to4 but their still not compatible.