Verifying whether an IPv6 IP is a LAN
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What is the question? Do you mean how to check whether address belongs to ranges (fe80::—febf:: , fec0::—feff:: ), i.e. whether it is site-local or link-local ? – Maxim Sagaydachny Apr 22 '20 at 10:51
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@MaximSagaydachny, Site-Local addressing was deprecated years ago in favor of ULA (Unique Local Addressing). There is no more Site-Local addressing. We have Link-Local (`fe80::/10`, but you have a lot of required zero bits so it is really `fe80::/64`) or ULA (`fc00::/7` of which only `fd00::/8` is available for assignment, but the next 40 bits are required to be randomly chosen). – Ron Maupin Apr 22 '20 at 15:00
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All Global addresses are in the `2000::/3` range. There are a few special address ranges in that block that cannot be globally routed, but you can check on that in the _[IANA IPv6 Special-Purpose Address Registry](https://www.iana.org/assignments/iana-ipv6-special-registry/iana-ipv6-special-registry.xhtml)_ where you can seep if a range is global, routable, can be used as a source or destination address, etc. – Ron Maupin Apr 22 '20 at 15:20
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IPv6 Global addresses are also used on a LAN. IPv6 restores the end-to-end paradigm of IP that was broken with NAT (IPv6 does not have NAT). The Link-Local addresses that all interfaces have will only work on that LAN, and ULA addresses can be used within an entire company as routable addresses, but cannot be used on the public Internet. Most hosts will get a Global address, too, that can be use on both the LAN and public Internet. – Ron Maupin Apr 22 '20 at 15:23