IPV6/IPV4 resolution-less forwarding up to a destination

1. A method, comprising:

intercepting, at a switch in a computer network, a packet originating from outside a layer 2 domain toward a destination target, the packet having a solicited node multicast address of the destination target as a destination media access control (MAC) address of the packet, wherein the solicited node multicast address is rewritten as the destination MAC in response to a router receiving the packet upon entry into the layer 2 domain not having adjacency for the destination target instead of performing address resolution for the packet;

determining whether the solicited node multicast address is a hit or miss within a switch hardware table of the switch;

in response to a hit, re-writing the destination MAC address with a known value of the destination target from the table; and

unicasting the packet to the destination target.

2. The method as in claim 1 , further comprising:

in response to a miss, and in response to a single-switch architecture, dropping the packet.

3. The method as in claim 1 , further comprising:

in response to a miss, and in response to a multi-switch architecture:

computing a repository switch for the solicited multicast destination; and

unicasting the packet to the computed repository switch.

4. The method as in claim 3 , further comprising:

receiving, from the repository switch, a redirect message instructing the switch to send future packets directly to a given access switch.

5. The method as in claim 1 , wherein the table is a ternary content addressable memory (TCAM).

6. The method as in claim 1 , further comprising:

enabling the intercepting in response to administrator control.

7. The method as in claim 1 , further comprising:

enabling the intercepting in response to detecting a triggering event.

8. The method as in claim 7 , wherein the triggering event is an attack.

9. An apparatus, comprising:

one or more network interfaces to communicate as a switch in a computer network;

a processor coupled to the network interfaces and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to:

intercept a packet originating from outside a layer 2 domain toward a destination target, the packet having a solicited node multicast address of the destination target as a destination media access control (MAC) address of the packet, wherein the solicited node multicast address is rewritten as the destination MAC in response to a router receiving the packet upon entry into the layer 2 domain not having adjacency for the destination target instead of performing address resolution for the packet;

determine whether the solicited node multicast address is a hit or miss within a switch hardware table of the switch;

in response to a hit, re-write the destination MAC address with a known value of the destination target from the table; and

unicast the packet to the destination target.

10. The apparatus as in claim 9 , wherein the process when executed is further operable to:

in response to a miss, and in response to a single-switch architecture, drop the packet.

11. The apparatus as in claim 9 , wherein the process when executed is further operable to:

in response to a miss, and in response to a multi-switch architecture:

compute a repository switch for the solicited multicast destination; and

unicast the packet to the computed repository switch.

12. The apparatus as in claim 11 , wherein the process when executed is further operable to:

receive, from the repository switch, a redirect message instructing the switch to send future packets directly to a given access switch.

13. The apparatus as in claim 9 , wherein the table is a ternary content addressable memory (TCAM).

14. The apparatus as in claim 9 , wherein the process when executed is further operable to:

enable the intercepting in response to administrator control.

15. The apparatus as in claim 9 , wherein the process when executed is further operable to:

enable the intercepting in response to detecting a triggering event.

16. The apparatus as in claim 15 , wherein the triggering event is an attack.

17. A tangible, non-transitory, computer-readable media having software encoded thereon, the software, when executed by a processor on a switch in a computer network, operable to:

intercept a packet originating from outside a layer 2 domain toward a destination target, the packet having a solicited node multicast address of the destination target as a destination media access control (MAC) address of the packet, wherein the solicited node multicast address is rewritten as the destination MAC in response to a router receiving the packet upon entry into the layer 2 domain not having adjacency for the destination target instead of performing address resolution for the packet;

determine whether the solicited node multicast address is a hit or miss within a switch hardware table of the switch;

in response to a hit, re-write the destination MAC address with a known value of the destination target from the table; and

unicast the packet to the destination target without any address resolution.

18. The computer-readable media as in claim 17 , wherein the software when executed is further operable to:

in response to a miss, and in response to a single-switch architecture, drop the packet.

19. The computer-readable media as in claim 17 , wherein the software when executed is further operable to:

in response to a miss, and in response to a multi-switch architecture:

compute a repository switch for the solicited multicast destination; and

unicast the packet to the computed repository switch.

20. The computer-readable media as in claim 17 , wherein the software when executed is further operable to:

receive, from the repository switch, a redirect message instructing the switch to send future packets directly to a given access switch.