Nov
29
So I’ve been sitting here trying to figure something out…then all the sudden it dawns on me … duhhhhhhh, I’m an idiot!
Here is the situation. R7—R8 …pretty basic. R7 connects to R8 direct via Serial0/0 on both sides, also there is a tunnel, tunnel0 on both sides. R8 has a loopback of 200.0.0.8 that it is redistributing into OSPF. I am sitting on R7 looking at the route for 200.0.0.8 trying to figure out why I am learning it via Tun0 instead of S0/0…I mean after all S0/0 has a much better metric right?
The serial link is 150.100.78.0/24 and the tunnel is 150.100.178.0/24. The serial links are area 78 and the tunnel is area 0.
R7#sh run | beg ospf 1
router ospf 1
log-adjacency-changes
area 78 stub
network 150.100.78.0 0.0.0.255 area 78
network 150.100.178.0 0.0.0.255 area 0
R8#sh run | beg router ospf 1
router ospf 1
log-adjacency-changes
area 78 stub
redistribute connected subnets
network 150.100.78.0 0.0.0.255 area 78
network 150.100.81.0 0.0.0.255 area 78
network 150.100.178.0 0.0.0.255 area 0
R7#sh ip route | i 200.0.0.8
O E2 200.0.0.8 [110/20] via 150.100.178.8, 00:15:25, Tunnel0
Can you guys see WHY I am getting this route learned via the tunnel? It’s so painfully obvious now that I look at it….
– Joe
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4 Responses to “Another One Of Those “DUHHHHH!!!” Moments”
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I was going to say it’s an area 0 thing (area 0 routes being preferred over non-area 0 routes), until I noticed the stub statement. You’re redistributing connected routes into the process, meaning they will show up as OSPF external routes. Area 78 is a stub area, so no external routes will be advertised, so the route is learned over the area 0 link. I’m pretty sure that’s the right answer, but it certainly is my best guess
.
Nick
Hi,
Is it something linked to Area0/AreaX preferency?? If we learn the same route through area 0 and a secondary area, the router would prefer the route learned via area 0, whatever the metrics values.
Am I right?
I didn’t look long…but area 78 is a stub.
Yep…area 78 is a stub!!! Cannot redistribute routes into a stub area!