Route table behavior when a static route exists and is active, and a route learned via OSPF is also present.

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Route table behavior when a static route exists and is active, and a route learned via OSPF is also present.

L2 Linker

Hi,

We have static routes in place at 7 sites for routing between sites.

In addition we are learning routes via OSPF, and these are set to a higher admin cost so not active.

So the static route is active.

 

When we look in the "runtime stats" route table (Not the forwarding table) of the virtual router, we only see the static routes currently, and we don't see the routes we are learning over OSPF.

If we delete the static route, the OSPF route then appears in the routing table.

 

I was sure all routes (static and dynamic) should be present in the route table, and only active routes would appear in the forwarding table.

Has a recent patch perhaps changed the default behaviour here? 

Should both dynamic and static routes be visible (even though only the static is active)

 

Many thanks.

 

 

 

 

6 REPLIES 6

L4 Transporter

Hi there,

What you describe is expected behaviour.

The routing table (show routing route) displays all of the prefixes with the 'best' (lowest administrative distance) along with other attributes from all routing protocols running on the firewall which have not been filtered. The forwarding table (show routing fib) shows the prefix along with next-hop and egress interface.

The OSPF LSDB is where you need to look for prefixes received from adjacent neighbours.

 

cheers,

Seb.

Thanks for the reply Seb.

 

So looking at 2 sites I have, I am seeing different behaviour.

 

When I run "show routing protocol OSPF LSDB" at both sites, I see the 172.30.10 is being learned.

However when I look at the runtime stats in the virtual router, one of the sites displays the OSPF route, and the other one doesn't.

In neither site is the OSPF route active.

Site 1 below showing Static and OSPF route.

CyberEng_0-1690807346037.png

 

Site 2 only showing Static route 

CyberEng_1-1690807506060.png

As I say, I see the OSPF route in the LSDB on both firewalls.

 

I'm cant think of a reason why the behaviour would be different.  

 

Cheers!

 

L4 Transporter

Interesting. On the FW with both prefixes in the routing table have the VR default Administrative Distance values been changed? Are both FWs running the same version?

 

cheers,

Seb.

L2 Linker

AD looks the same on both firewalls so no changes.  Both running 10.2.4h2.

We had an outage on a circuit this week, and based on what I was seeing at the site with the ospf route being displayed, I thought we had lost OSPF for the rest of the sites.  Not the case though as when you directed me towards the LSDB they are all there.  Thats what prompted me to investigate.  I was convinced we always saw routes from different protocols active or not.

L2 Linker

 I should add, the neighbors are not the palo altos - the neighbors are 3rd party appliances from our WAN provider. Just in case that could be a factor.

However im ruling that out for now as we see the entries in the LSDB.

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