Some computers, particularly those being managed by group policies at large businesses or schools, may have IPv6 turned off. IPv6 is required for all current Melco machine models to be able to connect to the computer through an available ethernet port.
You may see it turned on under Ethernet Properties. However, many group policies will disable IPv6 in the background - a setting which persists even after the computer is removed from the domain.
To re-enable IPv6, modify the registry key found at:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters\
When disabled, this parameter will appear as:
Decimal 255, or
Hexadecimal 0xFF
To re-enable, set to:
Decimal 32, or
Hexadecimal 0x20
The computer must be restarted for these changes to take effect.
More information on this registry entry can be found here.