Final answer:
The assertion that EUI-64 auto-generates the network portion of an IPv6 address is false; it is used to generate the interface identifier, which comprises the last 64 bits of the IPv6 address.
Step-by-step explanation:
The statement that EUI-64 specifies how the network portion of the IPv6 address is auto-generated is false. EUI-64 is actually a method for generating the interface identifier (the host portion) of an IPv6 address, using a 48-bit MAC address to create a unique 64-bit interface identifier. This is part of the IPv6 address autoconfiguration process, which allows a device on an IPv6 network to automatically generate its own IPv6 address without the need for manual configuration or a DHCP server.
More specifically, EUI-64 takes the 48-bit MAC address, splits it in half, inserts a fixed 16-bit pattern (FF-FE) in the middle, and flips the universal/local (U/L) bit. This operation transforms the MAC address into a 64-bit identifier that is used as the last 64 bits of the 128-bit IPv6 address, the first 64 bits of which are generally the network prefix assigned to the network.