OSPF wildcard mask question

kypumper

I know if you have a wan link the subnet mask is 255.255.255.252 or /30
so if you were going to set a OSPF network wildcard mask for ip address 10.10.10.1 it would be:
network 10.10.10.0 0.0.0.3 area 0

I saw an example in the ICND book that makes Wildcard masks easier.
Instead of trying to figure out the mask just type your exact ip.
network 10.10.10.1 0.0.0.0 area 0

It is suppose to better for security since no other IP address could update the routing table, but my question is does it matter which way you do it on the CCNA exam?

dissolved

kypumper wrote:

I know if you have a wan link the subnet mask is 255.255.255.252 or /30
so if you were going to set a OSPF network wildcard mask for ip address 10.10.10.1 it would be:
network 10.10.10.0 0.0.0.3 area 0

I saw an example in the ICND book that makes Wildcard masks easier.
Instead of trying to figure out the mask just type your exact ip.
network 10.10.10.1 0.0.0.0 area 0

It is suppose to better for security since no other IP address could update the routing table, but my question is does it matter which way you do it on the CCNA exam?

The way I did it on the test was 0.0.0.3

AceAll

I dont think it would matter.

QUIX0TIC

It wouldnt matter if you only have two routers updating any routing table. But, if you have more than two routers then you would have to create mutliple line entries so you can get all the applied routers.

My advice would be to use the 0.0.0.3 in which that is what they are looking for. But, you are correct that in the security sense, you can isolate the router to only one other router for updates.

darkuser

all you are doing is having an interface participate in ospf
you should be as specific as possible or you could overlap address spaces.

network 10.10.10.1 0.0.0.0 area 0
is correct.

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fipr_c/ipcprt2/1cfospf.htm