Ospf network Statement

Answered Question

Hello,

I am just wondering if someone can guide me to a document or kindly explain.


If i have 2 networks say 10.10.10.0 255.255.255.0 and 192.168.10.0 255.255.255.0


then under ospf i should have the statements like this



router ospf 1

network 10.10.10.0 0.0.0.255 area 0

network 192.168.10.0 0.0.0.255 area 0


BUT...


if i put


router ospf 1

network 0.0.0.0 255.255.255.255 area 0


then would both the above are same or not. I was told they are same. I have been searching the website but cannot get the concept or a document which can explain...



Correct Answer by Edison Ortiz about 9 years 1 week ago

They are not the same.


The first one will only enable OSPF on interfaces belonging to subnet 10.10.10.0/24 and 192.168.10.0/24


The second one will enable OSPF on any interface in the router. If you were to create a loopback interface, this interface will also be included into OSPF and this can cause some problems if you did not intend to do so.


The network 0.0.0.0 255.255.255.255 area 0 is basically telling the router to enable OSPF on any interface that this router has. Not a recommended solution on production environment.


HTH,


__


Edison.

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Correct Answer
Edison Ortiz Thu, 03/13/2008 - 10:37
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They are not the same.


The first one will only enable OSPF on interfaces belonging to subnet 10.10.10.0/24 and 192.168.10.0/24


The second one will enable OSPF on any interface in the router. If you were to create a loopback interface, this interface will also be included into OSPF and this can cause some problems if you did not intend to do so.


The network 0.0.0.0 255.255.255.255 area 0 is basically telling the router to enable OSPF on any interface that this router has. Not a recommended solution on production environment.


HTH,


__


Edison.

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