Site Local Address - FC00::/7
Site local address is IPv6's counter part to IPv4's private address space (as defined in RFC 1918
). It is
typically used within a site or organization. This type of address is not globally routable meaning you can't access this type of address from the internet.
reserved the block FEC0::/10 for site local address but this has since been deprecated and replaced with
FC00::/7 for used in private networks as defined in RFC 4193
FC00::/7 is further divided into two /8 subnets:
- FC00::/8 - the usage of this block has not been clearly defined.
- FD00::/8 - the routing prefix is formed by appending 40-bit of randomly-generated bit string in the format of
FDxx:xxxx:xxxx::/48 leaving the network administrator with 16 bit for subnetting and 64 bit for network identifier.
Site local address can be identify by the first 8 bits of any given IPv6 address. They should match either 11111100 or 11111101.
- 8 bitsPrefix
- 40 bitsrandom bit string
- 16 bitsSubnet
- 64 bitsInterface ID
Click on this link to examine Site Local address using the Advanced Online IPv6 Subnet Calculator: