CCNP Route FAQ: EIGRP Route Summarization and Filtering
Q1. Router R1 has been configured for EIGRP. The configuration also includes an ACL with one line–access-list 1 permit 10.100.32.0 0.0.15.255–and the EIGRP configuration includes the distribute-list 1 in command. Which of the following routes could not be displayed in the output of the show ip eigrp topology command as a result?
Q2. The command output that follows was gathered from router R1. If correctly referenced by an EIGRP distribution list that filters outbound Updates, which of the following statements is true about the filtering of various prefixes by this Prefix list?
R1#sh ip prefix-list
ip prefix-list question: 4 entries
seq 5 deny 10.1.2.0/24 ge 25 le 27
seq 15 deny 10.2.0.0/16 ge 30 le 30
seq 20 permit 0.0.0.0/0
a. Prefix 10.1.2.0/24 will be filtered due to clause 5.
b. Prefix 10.1.2.224/26 will be filtered due to clause 5.
c. Prefix 10.2.2.4/30 will be filtered due to clause 15.
d. Prefix 10.0.0.0/8 will be permitted.
e. Prefix 0.0.0.0/0 will be permitted.
Q3. R1 has correctly configured EIGRP to filter routes using a route map named question. The configuration that follows shows the entire route map and related configuration. Which of the following is true regarding the filtering action on prefix 10.10.10.0/24 in this case?
route-map question deny 10
match ip address 1
route-map question permit 20
match ip address prefix-list fred
access-list 1 deny 10.10.10.0 0.0.0.255
ip prefix-list fred permit 10.10.10.0/23 le 25
a. It will be filtered due to the deny action in route map clause 10.
b. It will be allowed because of the double negative (two deny references) in clause 10.
c. It will be permitted due to matching clause 20’s reference to prefix-list fred.
d. It will be filtered due to matching the implied deny all route map clause at the end of the route map.
Q4. An engineer has typed four different single-line prefix lists in a word processor. The four answers show the four different single-line prefix lists. The engineer then does a copy/paste of the configuration into a router. Which of the lists could match a subnet whose prefix length is 27?
a. ip prefix-list fred permit 10.0.0.0/24 ge 16 le 28
b. ip prefix-list barney permit 10.0.0.0/24 le 28
c. ip prefix-list wilma permit 10.0.0.0/24 ge 25
d. ip prefix-list betty permit 10.0.0.0/24 ge 28
Q5. An engineer plans to configure summary routes with the ip summary-address eigrp asn prefix mask command. Which of the following, when added to such a command, would create a summary that includes all four of the following subnets: 10.1.100.0/25, 10.1.101.96/27, 10.1.101.224/28, and 10.1.100.128.25?
a. 10.1.0.0 255.255.192.0
b. 10.1.64.0 255.255.192.0
c. 10.1.100.0 255.255.255.0
d. 10.1.98.0 255.255.252.0
Q6. R1 has 5 working interfaces, with EIGRP neighbors existing off each interface. R1 has routes for subnets 10.1.1.0/24, 10.1.2.0/24, and 10.1.3.0/24, with EIGRP integer metrics of roughly 1 million, 2 million, and 3 million, respectively. An engineer then adds the ip summary-address eigrp 1 10.1.0.0 255.255.0.0 command to interface Fa0/0. Which of the following is true?
a. R1 loses and then reestablishes neighborships with all neighbors.
b. R1 no longer advertises 10.1.1.0/24 to neighbors connected to Fa0/0.
c. 1 advertises a 10.1.0.0/16 route out Fa0/0, with metric of around 3 million (largest metric of component subnets).
d. R1 advertises a 10.1.0.0/16 route out Fa0/0, with metric of around 2 million (median metric of component subnets).
Q7. In a lab, R1 connects to R2, which connects to R3. R1 and R2 each have several working interfaces, all assigned addresses in class A network 10.0.0.0. Router R3 has some working interfaces in class A network 10.0.0.0, and others in class B network 172.16.0.0. The engineer experiments with the auto-summary command on R2 and R3, enabling and disabling the command in various combinations. Which of the following combinations will result in R1 seeing a route for 172.16.0.0/16, instead of the individual subnets of class B network 172.16.0.0?
a. auto-summary on R2 and no auto-summary on R3
b. auto-summary on R2 and auto-summary on R3
c. no auto-summary on R2 and no auto-summary on R3
d. no auto-summary on R2 and auto-summary on R3
Q8. Router R1 exists in an Enterprise that uses EIGRP as its routing protocol. The show ip route command output on router R1 lists the following phrase: “Gateway of last resort is 18.104.22.168 to network 22.214.171.124”. Which of the following is most likely to have caused this output to occur on R1?
a. R1 has been configured with an ip default-network 126.96.36.199 command.
b. R1 has been configured with an ip route 0.0.0.0 0.0.0.0 188.8.131.52 command.
c. R1 has been configured with an ip route 184.108.40.206 255.0.0.0 220.127.116.11 command.
d. Another router has been configured with an ip default-network 18.104.22.168 command.
e. Another router has been configured with an ip route 22.214.171.124 255.0.0.0 126.96.36.199 command.
Q9. Enterprise Router R1 connects an Enterprise to the Internet. R1 needs to create and advertise a default route into the Enterprise using EIGRP. The engineer creating the implementation plan has chosen to base this default route on the ip route command, rather than using ip default-network. Which of the following is not a useful step with this style of default route configuration?
a. Create the default route on R1 using the ip route 0.0.0.0 0.0.0.0 outgoinginterface command.
b. Redistribute the statically configured default route.
c. Disable auto-summary.
d. Configure the network 0.0.0.0 command.
e. Ensure R1 has no manually configured summary routes using the ip summary-address eigrp command.