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Bronze

Can't Install OSPF Prefix Into RIB

I have a router learning a default route from a neighbor OSPF router. The database entry looks as follows:

Router#sh ip ospf data ext 0.0.0.0

            OSPF Router with ID (1.1.1.1) (Process ID 100)

                Type-5 AS External Link States

  LS age: 1810
  Options: (No TOS-capability, DC)
  LS Type: AS External Link
  Link State ID: 0.0.0.0 (External Network Number )
  Advertising Router: 172.16.0.1
  LS Seq Number: 80000002
  Checksum: 0xAD1E
  Length: 36
  Network Mask: /0
        Metric Type: 2 (Larger than any link state path)
        TOS: 0
        Metric: 1
        Forward Address: 10.0.0.1
        External Route Tag: 100

The forward address is on a subnet directly connected to this router (10.0.0.0/24). This is a vlan stretched between two datacenters.

I'm not sure why the default route will not install into the RIB. If I remove the 10.0.0.0/24 interface on the upstream OSPF router so that the forward address is all zeros, the route is then installed into the RIB, but I need that interface to be running OSPF.

Does anyone have an idea why the default route will not install into the RIB? I appreciate the help.

4 REPLIES
Hall of Fame Super Silver

Can't Install OSPF Prefix Into RIB

Perhaps you could post the OSPF configuration of the router? This might give us additional information to help understand the issue.

HTH

Rick

Bronze

Re: Can't Install OSPF Prefix Into RIB

Neighbor router:

router ospf 100

log-adjacency-changes

network 10.0.0.0 0.0.0.255 area 0

network 192.168.1.0 0.0.0.255 area 0

network 192.168.2..0 0.0.0.255 area 0

network 192.168.0.0 0.0.0.3 area 0

network 192.168.0.60 0.0.0.3 area 0

network 192.168.0.64 0.0.0.3 area 0

network 192.168.0.68 0.0.0.3 area 0

network 192.168.0.72 0.0.0.3 area 0

network 192.168.0.76 0.0.0.3 area 0

network 192.168.0.80 0.0.0.3 area 0

network 192.168.0.84 0.0.0.3 area 0

network 192.168.0.88 0.0.0.3 area 0

default-information originate route-map RELIABLY_TRACK_FIREWALL

Router that wont install the default route:

router ospf 100

log-adjacency-changes

network 192.149.122.0 0.0.0.255 area 0

network 192.168.15.0 0.0.0.255 area 0

network 192.168.23.0 0.0.0.255 area 0

network 192.168.0.76 0.0.0.3 area 0

network 192.168.0.100 0.0.0.3 area 0

network 192.168.0.104 0.0.0.3 area 0

network 192.168.0.108 0.0.0.3 area 0

network 192.168.0.112 0.0.0.3 area 0

network 192.168.0.116 0.0.0.3 area 0

network 192.168.0.120 0.0.0.3 area 0

network 192.168.0.124 0.0.0.3 area 0

default-information originate metric 100 route-map RELIABLY_TRACK_FIREWALL

The route map matches a dummy route in the RIB that tracks an ICMP IPSLA. The SLA is up, dummy route is installed into RIB and default route originated, external LSA is sent and received. Just can't figure out why it can't be installed into the RIB

Thanks.

Bronze

Re: Can't Install OSPF Prefix Into RIB

I think I have it figured out.

I see the following from a "debug ip ospf spf external"

*Mar  1 02:13:08.103: OSPF:   more specific non-OSPF route to forwarding address

Sounds like I'm running into the issues described here: https://supportforums.cisco.com/docs/DOC-4450

I changed the interface for the spanned/transit network (10.0.0.0/24) to point-to-point (since they don't peer OSPF over those interfaces anyways) and the route was installed into the RIB.

Thanks.

Hall of Fame Super Silver

Can't Install OSPF Prefix Into RIB

I am glad that you got it figured out. Thanks for posting back to the forum indicating that it is solved and what you did to solve it. This may be useful for other readers of the forum.

HTH

Rick

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