isatap

ISATAP ((en) Intra-Site Automatic Tunnel Addressing Protocol) est un mécanisme de transition de l'IPv4 vers l'IPv6, qui permet de transmettre des paquets de données au format IPv6 à travers un réseau IPv4.

How ISATAP works

ISATAP defines a method for generating a link-local IPv6 address from an IPv4 address, and a mechanism to perform Neighbor Discovery on top of IPv4.

Link-local address generation

Any host wishing to participate in ISATAP over a given IPv4 network can set up a virtual IPv6 network interface. The link-local address is determined by concatenating fe80:0000:0000:0000:0200:5efe: for global unique and fe80:0000:0000:0000:0000:5efe: for private addresses with the 32 bits of the host's IPv4 address.
For example, host 192.0.2.143 would use fe80:0000:0000:0000:0200:5efe:192.0.2.143 as its link-local IPv6 address. A shortened notation would be fe80::200:5efe:c000:028f (192.0.2.143 is c000028f in hexadecimal notation).