Observe the following network presented in this exhibit carefully. Assume that all routers are
running EIGRP in AS 100 on all connected links. If the link between R3 and R4 is down, how
many queries will R5 and R6 receive?

A.
R5 will receive two queries, one for 192.168.1.0/24 and one for 192.168.2.0/24. R6 will receive
one query, for 192.168.2.0/24.

B.
R5 will receive one query, for 192.168.1.0/24, and R6 will receive no queries

C.
Both R5 and R6 will receive two queries, one for 192.168.1.0/24 and one for 192.168.2.0/24

D.
Neither R5 nor R6 will receive any queries for either 192.168.1.0/24 or 192.168.2.0/24.

Explanation:
R4 will go into an active state and send query about the both routes to R5. R5 at that moment
have no record in his eigrp topology table for the route 192.168.2.0/24 as this route has been
filtered by distribute list. So R5 will reply immediately to the router R4 telling him that route
192.168.2.0/24 is unreachable. As for the query for the route 192.168.1.0/24, R5 at that moment
has the record in his eigrp topology database for this route pointing back to the router R4. This is
why R4 will send only one query to router R6 asking for the path to the route
192.168.2.0.
Incorrect answers
B) R5 will receive two queries, for 192.1 68.1.0/24, and for 192 1682 0/24 as distribute list filters
only EIGRP updates messages.
C) Only R5 will receive the one message with two queries, for 192.168.1.0/24 and for 192 1682
0/24 R5 will not send query for 192 1682 0/24 to the router R6 as R5 had no record forthis route at
the moment of receiving the query from R4.

D) R5 will receive two queries, one for 192.168.1.0/24 and one for 192 1682 0/24 R6 will receive
one query, for 192 1682 0/24.

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094cb7.shtml#queri
es