Dell M6220 User Configuration Manual page 1103

• ipv6 route 2001::/16 null 254
ipv6 route 2002::/16 null 254
These address ranges are reserved and not reachable in the Internet. If for
some reason you have local networks in this range, a more specific route
will have precedence.
Another use for the Reject route is to prevent internal hosts from
communication with specific addresses or ranges of addresses. The effect is
the same as an outgoing access-list with a "deny" statement. A route is
generally more efficient than an access-list that performs the same function.
If you need more fine-grained filtering, such as protocols or port numbers, use
the access-list instead.
Configuring IPv6 Routing
1103