OSPF wildcard mask question

kypumperkypumper Posts: 35Member ■■□□□□□□□□
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?
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Comments

  • dissolveddissolved Posts: 228Inactive Imported Users
    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
  • AceAllAceAll Posts: 36Member ■■□□□□□□□□
    I dont think it would matter.
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  • QUIX0TICQUIX0TIC Posts: 277Member
    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.
    "To realize one's destiny is a person's only obligation."
  • darkuserdarkuser Posts: 621Member
    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
    rm -rf /
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