From: Richard Dumoulin (richard.dumoulin@vanco.es)
Date: Mon Apr 12 2004 - 10:42:56 GMT-3
Ah ok I understand, let me copy/paste an e-mail I sent to Allan yersteday.
It is not about a production network but a CCBootcamp scenario in which
configuring the wild card mask was not doing the job:
From: Richard Dumoulin [mailto:richard.dumoulin@vanco.es
<mailto:richard.dumoulin@vanco.es> ]
Sent: Monday, April 12, 2004 6:39 AM
To: Allan Wells
Subject: RE: advertise ospf as 192.168.1.1 /29 0.0.0.0 area 0 and no t
0.0.0.7
Allan,
It's CCBootcamp scenario5.
Suppose 2 routers: R5 and R2 connected by ethernet (so it is a broadcast
media, very important)
OSPF is configured between them and the rest of the ospf cloud is behind R5.
So we have the following diagram:
OSPF CLOUD <---> R5 <--OSPF--> R2
The network between R2 and R5 is 137.20.20.0/24.
R5 is 137.20.20.10 and R2 is 137.20.20.1
There is a default route on R2 --> ip route 0.0.0.0 0.0.0.0 137.20.20.2
Also 137.20.20.2 host does not exist but the scenario asks to configure this
anyway :))
----------------------
The question says to announce the default route to the ospf cloud. This is
done by configuring "default-information originate" on R2. Now R2 becomes an
ASBR ok ?
Here comes the issue: if on R2 I configure "network 137.20.20.0 0.0.0.255
area 0" like I usually do then the default route will show on R5 like this:
O*E2 0.0.0.0/0 [110/1] via 137.20.20.2, 02:24:11, Ethernet0/0
Do you remember ? 137.20.20.2 does not exist !! And there is a loopback on
R2 which does not belong to any protocol so the ospf cloud won't be able to
reach it. And a requirement is to have connectivity to any ip address !!
Now if instead I configure R2 like this: "network 137.20.20.1 0.0.0.0 area
0" then R5 will see the default route like this:
O*E2 0.0.0.0/0 [110/1] via 137.20.20.1, 02:24:11, Ethernet0/0
137.20.20.1 is the asbr itself (R2) and now R5 and the ospf cloud will reach
R2's Loopback0
Allan, this is explained in the Netmasterclass paper. Just take some routers
and practice the scenario. Let me know if it has been helpful,
Regards,
--Richard
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