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QID:RTE211 - suggested answer not the best - Printable Version

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QID:RTE211 - suggested answer not the best - pablo701 - 06-05-2011

In this question we are required to redistribute only the default route from one EIGRP domain to another.
Obviously the default route in the route table is 0.0.0.0/0
If you want to match this route completely via ACL then we need
"access-list 100 permit ip 0.0.0.0 0.0.0.0    0.0.0.0 0.0.0.0" (This is an answer choice but is not chosen as the correct answer)
I have tried this in a lab and confirmed that it works as expected.

The above could also have been written as:
"access-list 100 permit ip host 0.0.0.0 host 0.0.0.0"

The answer that has been selected as correct  is "access 100 permit any host 0.0.0.0"
which means permit any route whose length is 0.
This did work in my lab but I think it's not the best answer.

Actually another answer choice "access-list 100 permit 100 ip host 0.0.0.0 any" also worked in my lab.
- permit prefix 0.0.0.0 on any length??

Please explain why the answer provided by h2p "access-list 100 permit ip any host 0.0.0.0" is the best answer compared with all the other answers.

thanks,

pablo




Re: QID:RTE211 - suggested answer not the best - sdunn96 - 06-06-2011

I had this question on my test.

Regarding the correct answer on H2P.

You can rule out #4, you can redistribute default routes between protocols.

The reason I think you can go w/ "any host 0.0.0.0"
Is because any == Source, any host on the LAN
host == Destination, a specific target for traffic.
0.0.0.0 == which is that specific destination, and how do we define a default route?? "ip route 0.0.0.0...."

And remember, we are feeding this ACL into a Re-distribute List.
So it will allow the default route from EIGRP 190, while blocking all others.