Changing Network Class

Unanswered Question
Nov 27th, 2007

Hi All

Sorry for my lack of knowledge re IOS. I do know that this is wrong and wondering how to change it

router ospf 1


network area 0

network area 29

network area 30

network area 31

That 132 network should be class B. Any tips on how to correct that would be much appreciated.

Thanks in advance

I have this problem too.
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alessandroye Tue, 11/27/2007 - 08:21


Step.1 you should enter to OSPF configuration mode

Step.2 delete 132 network

no network area 0

Step.3 add the corrected network

network area 0

Step.3 in the enable mode, save the configuration.

Or Step.2 and Step.3 go together, u can change the wildcard directly.

alessandroye Tue, 11/27/2007 - 09:09



Router#config terminal

Router(config)# router ospf 1


so that u can enter to OSPF mode.

Nagendra Kumar ... Tue, 11/27/2007 - 08:35

Hi Paul,

Please be adviced that, it is not mandatory that you need to configure for all class B address. wildcard mask in network command under ospf routing protocol, is just to match the interface IP address and place the same in configured area. For EX:

If you have and address configured in your router which needs to be in area 0, you still can configure "network area 0"


mohindersingh Tue, 11/27/2007 - 09:59

Hi Paulo,

172 is a class B network but OSPF is a classless protocol. so you can configure any mask depending on your requirement.

You can break a single B class into sevral C class networks.

So first see your requirement and if needed then only delete it.



glen.grant Tue, 11/27/2007 - 09:12

Why do you think it is wrong ? You have to look at the interfaces , maybe that particular network is all they want to advertise . That statement is not neccessarily wrong.

Edison Ortiz Tue, 11/27/2007 - 11:36

If you want to enable OSPF on interfaces with subnets mentioned above (132.1.1.* - 132.1.7.*) then yes, it won't work with the current network statement under OSPF.

network area 0

should do the job.

Keep in mind, the list of networks under the OSPF process do not represent the networks that are being advertised -in transit- but the list of interfaces this device has, which you want to enable OSPF.


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