350-401 Question #824: Real Exam Question with Answer & Explanation

Question

Lab Simulation 3 Guidelines This is a lab item in which tasks will be performed on virtual devices. - Refer to the Tasks tab to view the tasks for this lab item. - Refer to the Topology tab to access the device console(s) and perform the tasks. - Console access is available for all required devices by clicking the device icon or using the tab(s) above the console window. - All necessary preconfigurations have been applied. - Do not change the enable password or hostname for any device. - Save your configurations to NVRAM before moving to the next item. - Click Next at the bottom of the screen to submit this lab and move to the next question. - When Next is clicked, the lab closes and cannot be reopened. Topology Tasks Configure OSPF on both routers according to the topology to achieve these goals: 1. Ensure that all networks are advertised between the routers without using the "network" statement under the "router ospf" configuration section. 2. Configure a single command on both routers to ensure: - The DR/BDR election does not occur on the link between the OSPF neighbors. - No extra OSPF host routes are generated. 3. Use md5 authentication between the p2p links Answer: Task 1. Ensure that all networks are advertised between the routers without using the "network" statement "router ospf" configuration section. -> So we will configure OSPF under interface mode with the command "ip ospf {ospf-process} area {area-number}": On both R1 & R2: R1&R2(config)#interface Ethernet 0/0 R1&R2(config-if)#ip ospf 1 area 0 R1&R2(config)#interface lo0 R1&R2(config-if)#ip ospf 1 area 0 Note: There is another version of this task which asks to advertise networks with "network" statements and configure router-id with IP address of Lo0. Here is the solution in this case: R1(config)#router ospf 1 R1(config-router)#router-id 1.1.1.1 R1(config-router)#network 192.168.0.0 0.0.0.255 area 0 R1(config-router)#network 1.1.1.1 0.0.0.0 area 0 R2(config)#router ospf 1 R2(config-router)#router-id 2.2.2.2 R2(config-router)#network 192.168.0.0 0.0.0.255 area 0 R2(config-router)#network 2.2.2.2 0.0.0.0 area 0 Task 2. Configure a single command on both routers to ensure: + The DR/BDR election does not occur on the link between the OSPF neighbors. + No extra OSPF host routes are generated. R1&R2(config)#interface Ethernet 0/0 R1&R2(config-if)#ip ospf network point-to-point Note: After configuring "ip ospf network point-to-point" command you will not see any routes changed and the number of routes remain the same. In fact, the request "no extra OSPF host routes are generated" wants to tell us "don't use ip ospf network point-to-multipoint" command as this command generates extra /32 routes. Task 3. Use md5 authentication between the p2p links Note: This task is optional. You may or may not see this task so please read the requirements of the sim carefully R1&R2(config-if)#ip ospf message-digest-key 1 md5 MY_PASSWORD R1&R2(config-if)#ip ospf authentication message-digest Save the configuration R1#, R2#, R3#copy running-config startup-config Verification R1#show ip ospf interface Ethernet 0/0 Ethernet 0/0 is up, line protocol is up Internet Address 192.168.0.1/24, Area 0, Attached via Interface Enable Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1 ... Cryptographic authentication enabled Youngest key id is 1 R1#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 2.2.2.2 0 FULL/- 00:00:35 192.168.0.2 Ethernet 0/0

Options

• taskConfigure OSPF on both routers (R1 and R2) according to the topology to achieve the following goals: 1. Ensure all networks are advertised between the routers without using the "network" statement under the "router OSPF" configuration section. 2. Configure a single command on both routers to ensure that DR/BDR election does not occur on the link between OSPF neighbors and no extra OSPF host routes are generated. 3. Use MD5 authentication between the point-to-point (p2p) links.
• prerequisitesConsole access to R1 and R2 virtual devices.