Quick OSPF configuration question

mallyg27

I was doing a Boson practice exam and I configured OSPF correctly, I received the routes and was able to ping around and they still marked my answer wrong. Is it safe to assume that for the exam I should configure a network statement for each interface?
So assuming I have serial0/1 192.168.2.1/30 and serial0/0 192.168.2.2/30, I should use the following:

RouterA(config-router) # Network 192.168.2.1 0.0.0.3 area 10
RouterA(config-router) # Network 192.168.2.2 0.0.0.3 area 10

and not this:

RouterA(config-router) # Network 192.168.2.0 0.0.0.255 area 10

Both of them work but I'm assuming on the exam they want you to do a command for each interface.

NetworkVeteran

On the real exam, any sequence of commands that achieves the stated objectives seems to be graded correctly, in my experience.

martell1000

depends on. if it is part of the question to use specific network statements. look out for words like "efficient" or "exact" ...

SubnetZero

Technically what you've done works, however wording is key.

For example you could have just done this and enabled OSPF everywhere.

SV-Dist-2(config)#router ospf 1
SV-Dist-2(config-router)#netw 0.0.0.0 255.255.255.255 area 10
SV-Dist-2(config-router)#exit

Essentially I just enabled OSPF on every interface on my router regardless of subnet, but is this really what you want?

SV-Dist-2(config)#do sh ip o inter br
Interface PID Area IP Address/Mask Cost State Nbrs F/C
Lo0 1 10 10.186.57.4/32 1 LOOP 0/0
Gi6/2 1 10 10.186.56.54/30 1 WAIT 0/0
Gi6/1 1 10 10.186.56.30/30 1 WAIT 0/0
Vl1000 1 10 10.75.180.7/27 1 WAIT 0/0
Vl750 1 10 10.255.0.41/30 1 WAIT 0/0
Vl555 1 10 10.186.58.51/28 1 WAIT 0/0
Vl501 1 10 192.168.59.3/27 1 WAIT 0/0
Vl500 1 10 10.255.0.51/29 1 WAIT 0/0
Vl424 1 10 192.168.254.3/24 1 WAIT 0/0
Vl301 1 10 10.255.10.2/30 1 DOWN 0/0
Vl205 1 10 172.29.10.2/30 1 DOWN 0/0
Vl200 1 10 172.19.2.3/23 1 WAIT 0/0
Vl160 1 10 192.168.231.3/24 1 WAIT 0/0
Vl99 1 10 10.186.17.3/24 1 WAIT 0/0
Vl60 1 10 192.242.237.241/24 1 WAIT 0/0
Vl55 1 10 192.168.35.3/24 1 DOWN 0/0
Vl50 1 10 10.186.16.3/26 1 WAIT 0/0
Vl45 1 10 10.75.179.3/25 1 WAIT 0/0
Vl40 1 10 10.75.180.195/26 1 WAIT 0/0
Vl35 1 10 192.168.36.3/24 1 WAIT 0/0
Vl30 1 10 10.75.178.3/25 1 WAIT 0/0
Vl25 1 10 10.75.178.131/25 1 WAIT 0/0
Vl20 1 10 10.75.182.3/23 1 WAIT 0/0
Vl16 1 10 192.168.241.3/24 1 WAIT 0/0
Vl15 1 10 10.75.177.3/24 1 WAIT 0/0
Vl9 1 10 10.186.19.3/28 1 WAIT 0/0
Vl8 1 10 10.186.21.131/26 1 WAIT 0/0
Vl7 1 10 10.186.21.67/26 1 WAIT 0/0
Vl6 1 10 10.186.21.3/26 1 WAIT 0/0
Vl5 1 10 10.75.176.131/25 1 WAIT 0/0
Vl1 1 10 10.75.176.3/25 1 WAIT 0/0


The thing to remember is that the network command is just an enabler, so by using a wildcard mask of 0.0.0.255 you're saying "any" network that falls into this range will have OSPF enabled (even if it shouldn't)

In the CCIE lab I always recommend using the exact match so you don't bring in networks that shouldn't be there.

Just my .002...

Cheers

mallyg27

martell1000 wrote: »

depends on. if it is part of the question to use specific network statements. look out for words like "efficient" or "exact" ...

The question states " You should configure each router to properly announce the appropriate networks by using the networks address, not the interface IP address.

mallyg27

I just went back to that question. I understand what they mean now.