Editing IPv6 (section)

===ISP customers with public-facing IPv6===
[[File:IPv6 Prefix Assignment Example-en.svg|thumb|upright=1.2|IPv6 Prefix Assignment mechanism with IANA, RIRs, and ISPs]]

[[Internet service providers]] (ISPs) are increasingly providing their business and private customers with public-facing IPv6 global unicast addresses. If IPv4 is still used in the local area network (LAN), however, and the ISP can only provide one public-facing IPv6 address, the IPv4 LAN addresses are translated into the public facing IPv6 address using [[NAT64]], a [[network address translation]] (NAT) mechanism. Some ISPs cannot provide their customers with public-facing IPv4 and IPv6 addresses, thus supporting dual-stack networking, because some ISPs have exhausted their globally routable IPv4 address pool. Meanwhile, ISP customers are still trying to reach IPv4 [[web servers]] and other destinations.<ref>{{cite web|url=https://www.juniper.net/documentation/en_US/junos/topics/concept/ipv6-dual-stack-understanding.html|title=Understanding Dual Stacking of IPv4 and IPv6 Unicast Addresses|website=Juniper.net|publisher=Juniper Networks|date=31 August 2017|access-date=19 January 2022}}</ref>

A significant percentage of ISPs in all [[regional Internet registry]] (RIR) zones have obtained IPv6 address space. This includes many of the world's major ISPs and [[mobile network]] operators, such as [[Verizon Wireless]], [[StarHub|StarHub Cable]], [[Chubu Electric Power|Chubu Telecommunications]], [[Kabel Deutschland]], [[Swisscom]], [[T-Mobile International AG|T-Mobile]], [[Internode (ISP)|Internode]] and [[Telefónica]].<ref>{{cite web|url=https://www.nro.net/ipv6/|title=IPv6|website=NRO.net|access-date=13 March 2017|archive-date=12 January 2017|archive-url=https://web.archive.org/web/20170112052541/https://www.nro.net/ipv6|url-status=dead}}</ref>

While some ISPs still allocate customers only IPv4 addresses, many ISPs allocate their customers only an IPv6 or dual-stack IPv4 and IPv6. ISPs report the share of IPv6 traffic from customers over their network to be anything between 20% and 40%, but by mid-2017 IPv6 traffic still only accounted for a fraction of total traffic at several large [[Internet exchange point]]s (IXPs). [[AMS-IX]] reported it to be 2% and [[SeattleIX]] reported 7%. A 2017 survey found that many DSL customers that were served by a dual stack ISP did not request DNS servers to resolve fully qualified domain names into IPv6 addresses. The survey also found that the majority of traffic from IPv6-ready web-server resources were still requested and served over IPv4, mostly due to ISP customers that did not use the dual stack facility provided by their ISP and to a lesser extent due to customers of IPv4-only ISPs.<ref>{{Cite web |last=Pujol |first=Enric |date=12 June 2017 |title=What Stops IPv6 Traffic in a Dual-Stack ISP? |url=https://blog.apnic.net/2017/06/13/stops-ipv6-traffic-dual-stack-isp/ |url-status=live |archive-url=https://web.archive.org/web/20230327133355/https://blog.apnic.net/2017/06/13/stops-ipv6-traffic-dual-stack-isp/ |archive-date=27 March 2023 |access-date=13 June 2017 |website=APNIC.net |publisher=[[APNIC]] }}</ref>