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Replies

Changing Network Class

paul.dickinson
Level 1
Level 1

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

log-adjacency-changes

network 132.1.1.0 0.0.0.255 area 0

network 172.29.0.0 0.0.255.255 area 29

network 172.30.0.0 0.0.255.255 area 30

network 172.31.0.0 0.0.255.255 area 31

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

Thanks in advance

8 Replies 8

alessandroye
Level 1
Level 1

Ok,

Step.1 you should enter to OSPF configuration mode

Step.2 delete 132 network

no network 132.1.1.0 0.0.0.255 area 0

Step.3 add the corrected network

network 132.1.1.0 0.0.255.255 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.

I hate to ask but how do I get into OSPF config mode?

ena

config ? something?

Router>

Router>enable

Router#config terminal

Router(config)# router ospf 1

Router(config-router)#

so that u can enter to OSPF mode.

Nagendra Kumar Nainar
Cisco Employee
Cisco Employee

Hi Paul,

Please be adviced that, it is not mandatory that you need to configure 0.0.255.255 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 10.5.5.5/24 and 10.5.6.5/24 address configured in your router which needs to be in area 0, you still can configure "network 10.0.0.0 0.0.255.255 area 0"

Nagendra

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.

Regards

Mahi

glen.grant
VIP Alumni
VIP Alumni

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.

Well I think it is wrong because the network is using IP's 132.1.1.* - 132.1.7.*

Am I right?

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 132.1.0.0 0.0.7.255 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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