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ospf overrides connected route

surama123
Level 1
Level 1

Why does an e2 ospf route to a host override a route to a subnet containing that host that is locally connected?

 

So I have a host connected locally and the subnet appears in the routing table out of the local interface.

OSPF is learning a route to that host out of another interface.

I found it suprising but OSPF overrides the connected subnet, possibly because the route is more specific, ie to a host instead of a subnet.

Any thoughts on this would be appreciated.

1 Accepted Solution

Accepted Solutions

Hello surama123,

 

There you go. OSPF prefix is longer than connected.

 

Longer prefixes are always preferred over shorter ones when forwarding a packet.

 

 

Best regards,

 

DavidNoel

View solution in original post

4 Replies 4

davrojas
Level 3
Level 3

Hello surama,

 

Is it being override with a lower cost ?

By more specific i would ask: Is the prefix length longer?

 

Regards,

Pekiro

surama123
Level 1
Level 1

Thanks for your reply.

 

Connected route seems to have a cost of 0

OSPF prefix is /32

connected prefix is /28

 

Ian

Hello surama123,

 

There you go. OSPF prefix is longer than connected.

 

Longer prefixes are always preferred over shorter ones when forwarding a packet.

 

 

Best regards,

 

DavidNoel

Thanks for your reply DavidNoel,

I'm ashamed to say I didn't know such a basic rule blush.

All the best,

 

Ian