Is it even possible! :P

@Night: "not based on NAT"
I'm afraid it's going to be a long time before that happens.

"IPv6 via tunnel."
http://www.google.com/intl/en/ipv6/faq.html#tunnel

Depends on if you want to run in an environment you're not comfortable with, IPv6 doesn't need to be used for a few more years atleast. Lets wait for Windows. 8?

@Night, it should not matter at all as 97% of all current accessable clients are still using the IPv4 protocol. Until upstream providers allow native IPv6 access it shouldn't really be needed, especially for a port checker. :P

Dunno who the owner of that site is @Jonsey44, WHOIS doesn't return anything special.

So you know, IPv4 (What we, and you use currently) can only allocate 2^32, including reserved addresses that we can't use. That is roughly 4 billion, obviously not enough for the growing world. It is possible by 2013 it will be exhausted.

IPv6, which is partially in support (Google, and some sites /torrents and most Linux distributions) but there is yet still a huge leap to take to fulfill this jump.

IPv6 = 2¹²⁸ = A lot.

@Night. No, there will be enough addresses maybe to allow every partical in this universe internet allocations, but.. pointless to go there. :)