Interface Loopback0 not being announced in OSPF

[Rod Oliver]

I have an odd situation with a number of loopback interfaces in the network that I have started to work on. Even though the IP address on them are covered by a network statement under OPSF they are not being announced in OSPF. See the example below.

switch01#sh run int lo0
Building configuration...

Current configuration : 203 bytes
!
interface Loopback0
ip address 10.2.255.1 255.255.255.255
no ip redirects
no ip unreachables
no ip proxy-arp
no ip mroute-cache
ip ospf network point-to-point
end

switch01#sh run | b router ospf
router ospf 1
router-id 10.2.255.1
log-adjacency-changes
auto-cost reference-bandwidth 1000
area 0 authentication message-digest
area 1 authentication message-digest
area 1 range 10.2.224.0 255.255.240.0
redistribute static metric-type 1 subnets route-map STATIC_TO_OSPF
passive-interface default
no passive-interface Vlan232
<snip snip>
network 10.2.255.1 0.0.0.0 area 1
<snip snip>

Could it have something to do with the statement "ip ospf network point-to-point" on the loopback?

[Julio E. Moisa · Accepted solution]

Hi Rod,

What about if you include under the loopback0 the following command:

ip ospf 1 area 1

I dont know your IP Plan but I think you are advertising a range: area 1 range 10.2.224.0 255.255.240.0

You could include instead: area 1 range 10.2.224.0 255.255.224.0

So the network 10.2.255.0 will be included on the advertisement. Although the loopback0 should be advertised anyway how you has configured.

Is it on production? if not try to clear the ospf process: clear ip ospf process <press yes>

[Rod Oliver]

Hi Julio,

Thanks for your reply. After I looked some more into things, I realise that they were being announced, they just weren't visible due to static routes with the same address & mask were being redistributed into OSPF.