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ospf routing on ASA

bmak
Level 1
Level 1

Hi-

I am trying to figure out if a particular subnet is actively being learned by my ASA firewall.

When I check my "show route" output I do not see any entry for the subnet there.

However when I check the OSPF database on the firewall using the command "show ospf database",  I am able to see the subnet being learned and its adv router.

 

I would please like clarification on if the subnet being seen in the database(show ospf database output) means the ASA is actively learning about it even though it's not seen on the routing table (show route output) 

1 Accepted Solution

Accepted Solutions

Harold Ritter
Cisco Employee
Cisco Employee

Hi,

 

The reason is that the LSA is being received, but something is wrong with it. You can confirm it by doing a "show ospf data router <router-id>" for the given neighbor. You should see something like this in the output:

 

Adv Router is not-reachable

 

It could be due to the fact that you have a mismatch network type on either side of the adjacency (point-to-point on one side, broadcast on the other). This will not prevent the adjacency to form, but it will cause the issue that even though the router LSA is received, OSPF will not be able to calculate a valid path to prefixes on the connected router.

 

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

View solution in original post

2 Replies 2

Harold Ritter
Cisco Employee
Cisco Employee

Hi,

 

The reason is that the LSA is being received, but something is wrong with it. You can confirm it by doing a "show ospf data router <router-id>" for the given neighbor. You should see something like this in the output:

 

Adv Router is not-reachable

 

It could be due to the fact that you have a mismatch network type on either side of the adjacency (point-to-point on one side, broadcast on the other). This will not prevent the adjacency to form, but it will cause the issue that even though the router LSA is received, OSPF will not be able to calculate a valid path to prefixes on the connected router.

 

Regards,

Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México
Paseo de la Reforma 222
Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México

bmak
Level 1
Level 1

thank you for the explanation

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