OSPFv3 suppression of more specific routes problem

[tmikelson]

An IPv6 host on a different network can ping6 interface VLAN9 and interface Loopback0.

The command "area 18 range ABCD:EFAB:CDEF:A009::/64 not-advertise" is added to "ipv6 router ospf 101"

1) The more specific IPv6 route ABCD:EFAB:CDEF:A009::/64 disappears from core routing table.

2) An IPv6 host on a different network CANNOT ping6 interface VLAN9 but can reach interface Loopback0.

The desired behavior is for only the more general route ABCD:EFAB:CDEF:A000::/76 to appear in the core routing table and all IPv6 addresses in that range to be reachable.

NOTE: the very specific IPv6 address on interface Loopback0 ABCD:EFAB:CDEF:A000::1/128 never appears in the core routing table whether a range command for it is present or not.

***** IPv6 configuration ******

interface Vlan9
ip address (REDACTED)
ipv6 address ABCD:EFAB:CDEF:A009::1/64
ipv6 enable
ipv6 ospf 101 area 18
end

interface Loopback0
ip address 192.168.X.X 255.255.255.255
ipv6 address ABCD:EFAB:CDEF:A000::1/128
ipv6 enable
ipv6 ospf 101 area 18


ipv6 router ospf 101
router-id 192.168.X.X
log-adjacency-changes
area 18 range ABCD:EFAB:CDEF:A000::/76
passive-interface Vlan9

***** IPv6 routing table on core router *****

ABCD:EFAB:CDEF:A000::/76, ubest/mbest: 2/0
*via fe80::A:B:C:D, Vlan11, [110/81], 00:16:58, ospfv3-101, inter
*via fe80::F:E:D:C, Vlan11, [110/81], 00:16:58, ospfv3-101, inter
ABCD:EFAB:CDEF:A009::/64, ubest/mbest: 2/0
*via fe80::A:B:C:D, Vlan11, [110/82], 00:00:05, ospfv3-101, inter
*via fe80::F:E:D:C, Vlan11, [110/82], 00:00:05, ospfv3-101, inter

[Harold Ritter]

Hi @tmikelson ,

> 1) The more specific IPv6 route ABCD:EFAB:CDEF:A009::/64     > disappears from core routing table.

That is the expected behavior

> 2) An IPv6 host on a different network CANNOT ping6 interface > VLAN9 but can reach interface Loopback0.

Also expected behavior.

> The desired behavior is for only the more general route              > ABCD:EFAB:CDEF:A000::/76 to appear in the core routing table > and all IPv6 addresses in that range to be reachable.

It looks like it should be what you get from the routing table snapshot you provided.

> NOTE: the very specific IPv6 address on interface Loopback0 >ABCD:EFAB:CDEF:A000::1/128 never appears in the core routing >table whether a range command for it is present or not.

I am not sure what the topology is, but in principle you should see the /128 advertisements if you remove the range command.

[tmikelson · Accepted solution]

It took putting it in writing to see the error of my ways. I had reversed the netmask in the range command. Instead of /76 I needed /52. Once I made the change I saw the desired behavior just like with IPv4/OSPFv2.

[Harold Ritter]

I am glad you found the issue @tmikelson .