If the DHCP server option is enabled, you must be very careful in assigning
IP addresses of a filtered private IP range to avoid conflicts because you do
not know which PC in the LAN is assigned which IP address. The easiest
and safest way is that the filtered IP address is assigned to a specific PC
that is not allowed to access an outside resource such as the Internet. You
configure the filtered IP address manually for this PC, but it stays in the
same subnet with the router.
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