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Valid IPv6

Valid IPv6

Valid IPv6

I thought I knew what a valid IPv6 address looked like but obviously not.

So assuming you have only one set of ::'s, valid hex digits, the correct number of "16-bit sections", what can make an ipv6 address invalid?

Sorry if this is too vague.


RE: Valid IPv6


Depends on what you're using the address for. Here's a list of the most common blocks and their uses:

::/128 or ::0/128 = Unspecified (Typically used by a host when attempting to secure an address via DHCP)

::1/128 = Loopback (Think

FF00::/8 = Multicast (The two zeroes are replaced by Flag and Scope values depending on the use of the address)

FE80::/10 = Link Local Unicast (Typically generaed automatically by the host/device)
[ This address is ONLY valid on the link and CANNOT be used for routing traffic ]

FC00::/7 = Unique Local Addresses (ULA) intended to be used within a private network -- See RFC 4193 (Think RFC 1918)

2000::/3 = Global Unicast (These are actually assigned to devices for use on the Internet)
[ That's 2000::0 through 3FFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF ]

200::/7 = Reserved Unicast for NSAP allocation -- See RFC 1888 [ Note: This is 200::, NOT 2000:: ]

::FFFF:0:0:x.y.z.d/96 = IPv4-Mapped IPv6 Addresses (Replace the x.y.z.d with a "normal" 32-bit dotted-decimal IPv4 address. Typically used when moving from an IPv4 environment to IPv6 and you want your current IPv4 applications to continue working.)

Hope this helps.

vrs / fmj

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