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QID:RTE217 - please explain answer - Printable Version

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QID:RTE217 - please explain answer - pablo701 - 06-02-2011

Admin or Forum:

can you please explain the answer to question QID:RTE217?
This a question about redistribution between RIPV2 and OSPF (and vice-versa) and avoiding routing loops.
I think what needs to be done is to make sure that the routes advertised from OSPF to RIP and not advertized back from RIP to OSPF.

However, I do not understand how the the access-list with a deny clause works with the route-map with a deny clause.

I think the answer is not correct.

we need to stop 10.1.1.0 from being redistributed from RIP back to OSPF

stated answer:
   access-list 15 deny 10.1.1.0   0.0.0.63
   access-list 15 permit any  <-------

The above ACL will pass  to the route-map shown below all routes except 10.1.1.0
However the deny clause in the route-map will block all these routes from being redistributed - not the outcome be are looking for.

   route-map redis-rip deny 10
   match ip address 15

If you keep the ACL as-is, that is the ACL will pass all the routes that can be redistributed, then the route-map needs just one block:

route-map redis permit 10
match ip address 15.

"The route-map redis permit 20" is not needed.


(: all previous how2pass exams I had used had very good answer explanations. This 642-902 how2pass exam has a very high number of unexplained answers.

pablo



Re: QID:RTE217 - please explain answer - sdunn96 - 06-03-2011

At first glance, this looks like a type-o to me....
I think you are correct it should have been a permit on the re-dist list.

I will look at it again tomorrow.....see if something comes to me that is not hitting me now.