Q21. - (Topic 4) 

Refer to the exhibit. 

A company wants to use NAT in the network shown. Which commands will apply the NAT configuration to the proper interfaces? (Choose two.) 

A. R1(config)# interface serial0/1 R1(config-if)# ip nat inside 

B. R1(config)# interface serial0/1 R1(config-if)# ip nat outside 

C. R1(config)# interface fastethernet0/0 R1(config-if)# ip nat inside 

D. R1(config)# interface fastethernet0/0 R1(config-if)# ip nat outside 

E. R1(config)# interface serial0/1 R1(config-if)# ip nat outside source pool 200.2.2.18 255.255.255.252 

F. R1(config)# interface fastethernet0/0 R1(config-if)# ip nat inside source 10.10.0.0 255.255.255.0 

Answer: B,C 

Explanation: 

For NAT, you need to define which interfaces are inside and which are outside. The outside interface is the one that connects to the external network, and the one that will be used for translating addresses. The inside interface is for the internal network, and defines the network IP addresses that will get translated to the one specified in the outside network. 


Q22. - (Topic 3) 

The internetwork infrastructure of company XYZ consists of a single OSPF area as shown in the graphic. There is concern that a lack of router resources is impeding internetwork performance. As part of examining the router resources, the OSPF DRs need to be known. All the router OSPF priorities are at the default and the router IDs are shown with each router. 

Which routers are likely to have been elected as DR? (Choose two.) 

A. Corp-1 

B. Corp-2 

C. Corp-3 

D. Corp-4 

E. Branch-1 

F. Branch-2 

Answer: D,F 

Explanation: 

There are 2 segments on the topology above which are separated by Corp-3 router. Each 

segment will have a DR so we have 2 DRs. 

To select which router will become DR they will compare their router-IDs. The router with 

highest (best) router-ID will become DR. The router-ID is chosen in the order below: 

+

 The highest IP address assigned to a loopback (logical) interface. 

+

 If a loopback interface is not defined, the highest IP address of all active router’s physical interfaces will be chosen. 

In this question, the IP addresses of loopback interfaces are not mentioned so we will consider IP addresses of all active router’s physical interfaces. Router Corp-4 (10.1.40.40) 

& Branch-2 (10.2.20.20) have highest “active” IP addresses so they will become DRs. 


Q23. - (Topic 3) 

What is the default administrative distance of the OSPF routing protocol? 

A. 90 

B. 100 

C. 110 

D. 120 

E. 130 

F. 170 

Answer:

Explanation: 

Default Distance Value Table This table lists the administrative distance default values of the protocols that Cisco supports: If the administrative distance is 255, the router does not believe the source of that route and does not install the route in the routing table. 


Q24. CORRECT TEXT - (Topic 6) 

This topology contains 3 routers and 1 switch. Complete the topology. 

Drag the appropriate device icons to the labeled Device Drag the appropriate connections to the locations labeled Connections. Drag the appropriate IP addresses to the locations labeled IP address 

(Hint: use the given host addresses and Main router information) To remove a device or connection, drag it away from the topology. 

Use information gathered from the Main router to complete the configuration of any additional routers. 

No passwords are required to access the Main router. The config terminal command has been disabled for the HQ router. The router does not require any configuration. 

Configure each additional router with the following: 

Configure the interfaces with the correct IP address and enable the interfaces. 

Set the password to allow console access to consolepw 

Set the password to allow telnet access to telnetpw 

Set the password to allow privilege mode access to privpw 

Not E: Because routes are not being added to the configurations, you will not be able to ping through the internetwork. 

All devices have cable autosensing capabilities disabled. 

All hosts are PC’s 

Answer: Specify appropriate devices and drag them on the "Device" boxes For the device at the bottom-right box, we notice that it has 2 interfaces Fa0/2 and Fa0/4; moreover the link connects the PC on the right with the device on the bottom-right is a straight-through link -> it is a switch The question stated that this topology contains 3 routers and 1 switch -> two other devices are routers Place them on appropriate locations as following: (Host D and host E will be automatically added after placing two routers. Click on them to access neighboring routers) Specify appropriate connections between these devices: 

+

 The router on the left is connected with the Main router through FastEthernet interfaces: use a crossover cable 

+

 The router on the right is connected with the Main router through Serial interfaces: use a 

serial cable 

+

 The router on the right and the Switch: use a straight-through cable 

+

 The router on the left and the computer: use a crossover cable (To remember which type of cable you should use, follow these tips: 

-

To connect two serial interfaces of 2 routers we use serial cable 

-

To specify when we use crossover cable or straight-through cable, we should remember: Group 1: Router, Host, Server Group 2: Hub, Switch One device in group 1 + One device in group 2: use straight-through cable Two devices in the same group: use crossover cable For example, we use straight-through cable to connect switch to router, switch to host, hub to host, hub to server... and we use crossover cable to connect switch to switch, switch to hub, router to router, host to host.) Assign appropriate IP addresses for interfaces: From Main router, use show running-config command. 

 (Notice that you may see different IP addresses in the real CCNA exam, the ones shown above are just used for demonstration) 

From the output we learned that the ip address of Fa0/0 interface of the Main router is 

192.168.152.177/28. This address belongs to a subnetwork which has: 

Increment: 16 (/28 = 255.255.255.240 or 1111 1111.1111 1111.1111 1111.1111 0000) 

Network address: 192.168.152.176 (because 176 = 16 * 11 and 176 < 177) 

Broadcast address: 192.168.152.191 (because 191 = 176 + 16 - 1) 

And we can pick up an ip address from the list that belongs to this subnetwork: 

192.168.152.190 and assign it to the Fa0/0 interface the router on the left Use the same method for interface Serial0/0 with an ip address of 192.168.152.161 Increment: 16 Network address: 192.168.152.160 (because 160 = 16 * 10 and 160 < 161) Broadcast address: 192.168.152.175 (because 176 = 160 + 16 - 1) -> and we choose 192.168.152.174 for Serial0/0 interface of the router on the right Interface Fa0/1 of the router on the left IP (of the computer on the left) : 192.168.152.129/28 Increment: 16 Network address: 192.168.152.128 (because 128 = 16 * 8 and 128 < 129) Broadcast address: 192.168.152.143 (because 143 = 128 + 16 - 1) -> we choose 192.168.152.142 from the list Interface Fa0/0 of the router on the right IP (of the computer on the left) : 192.168.152.225/28 Increment: 16 Network address: 192.168.152.224 (because 224 = 16 * 14 and 224 < 225) Broadcast address: 192.168.152.239 (because 239 = 224 + 16 - 1) -> we choose 192.168.152.238 from the list Let's have a look at the picture below to summarize Configure two routers on the left and right with these commands: Router1 = router on the left Assign appropriate IP addresses to Fa0/0 & Fa0/1 interfaces: Router1>enable Router1#configure terminal Router1(config)#interface fa0/0 Router1(config-if)#ip address 192.168.152.190 255.255.255.240 Router1(config-if)#no shutdown Router1(config-if)#interface fa0/1 Router1(config-if)#ip address 192.168.152.142 255.255.255.240 Router1(config-if)#no shutdown Set passwords (configure on two routers) 

+

 Console password: Router1(config-if)#exit Router1(config)#line console 0 

Router1(config-line)#password consolepw Router1(config-line)#login Router1(config-line)#exit 

+

 Telnet password: Router1(config)#line vty 0 4 Router1(config-line)#password telnetpw Router1(config-line)#login Router1(config-line)#exit 

+

 Privilege mode password: Router1(config)#enable password privpw Save the configuration: Router1(config)#exit Router1#copy running-config startup-config Configure IP addresses of Router2 (router on the right) Router2>enable Router2#configure terminal Router2(config)#interface fa0/0 Router2(config-if)#ip address 192.168.152.238 255.255.255.240 Router2(config-if)#no shutdown Router2(config-if)#interface serial0/0 Router2(config-if)#ip address 192.168.152.174 255.255.255.240 Router2(config-if)#no shutdown Then set the console, telnet and privilege mode passwords for Router2 as we did for Router1, remember to save the configuration when you finished. 


Q25. - (Topic 2) 

Refer to the exhibit. 

The ports that are shown are the only active ports on the switch. The MAC address table is shown in its entirety. The Ethernet frame that is shown arrives at the switch. 

What two operations will the switch perform when it receives this frame? (Choose two.) 

A. The MAC address of 0000.00aa.aaaa will be added to the MAC address table. 

B. The MAC address of 0000.00dd.dddd will be added to the MAC address table. 

C. The frame will be forwarded out of port fa0/3 only. 

D. The frame will be forwarded out of fa0/1, fa0/2, and fa0/3. 

E. The frame will be forwarded out of all the active ports. 

Answer: A,D 

Explanation: 

If the switch already has the MAC address in its table for the destination, it will forward the frame directly to the destination port. If it was not already in its MAC table, then they frame would have been flooded out all ports except for the port that it came from. It will also add the MAC address of the source device to its MAC address table 


Q26. - (Topic 3) 

What is the OSPF default frequency, in seconds, at which a Cisco router sends hello packets on a multi-access network? 

A. 10 

B. 40 

C. 30 

D. 20 

Answer:

Explanation: 

On broadcast multiacess and point-to-point links, the default is 10 seconds. On NBMA, the default is 30 seconds. 


Q27. - (Topic 1) 

Which two characteristics apply to Layer 2 switches? (Choose two.) 

A. Increases the number of collision domains 

B. Decreases the number of collision domains 

C. Implements VLAN 

D. Decreases the number of broadcast domains 

E. Uses the IP address to make decisions for forwarding data packets 

Answer: A,C 

Explanation: 

Layer 2 switches offer a number of benefits to hubs, such as the use of VLANs and each switch port is in its own separate collision domain, thus eliminating collisions on the segment. 


Q28. - (Topic 3) 

Which IOS command is used to initiate a login into a VTY port on a remote router? 

A. router# login 

B. router# telnet 

C. router# trace 

D. router# ping 

E. router(config)# line vty 0 5 

F. router(config-line)# login 

Answer:

Explanation: 

VTY ports are telnet ports hence command B will initiate login to the telnet port. 


Q29. - (Topic 1) 

Refer to the exhibit. 

The exhibit is showing the topology and the MAC address table. Host A sends a data frame to host D. What will the switch do when it receives the frame from host A? 

A. The switch will add the source address and port to the MAC address table and forward the frame to host D. 

B. The switch will discard the frame and send an error message back to host A. 

C. The switch will flood the frame out of all ports except for port Fa0/3. 

D. The switch will add the destination address of the frame to the MAC address table and forward the frame to host D. 

Answer:

Explanation: 

When switch receives the data frame from the host not having the MAC address already on the MAC table, it will add the MAC address to source port on MAC address table and sends the data frame. 


Q30. - (Topic 5) 

The network administrator has found the following problem. 

The remote networks 172.16.10.0, 172.16.20.0, and 172.16.30.0 are accessed through the Central router's serial 0/0 interface. No users are able to access 172.16.20.0. After reviewing the command output shown in the graphic, what is the most likely cause of the problem? 

A. no gateway of last resort on Central 

B. Central router's not receiving 172.16.20.0 update 

C. incorrect static route for 172.16.20.0 

D. 172.16.20.0 not located in Central's routing table 

Answer:

Explanation: 

If we use 172.16.20.0 to route to 172.16.150.15, then the packet will route back. To clear this error we have to use.#no ip route 172.16.20.0 255.255.255.0 172.16.150.15

.command in configuration mode.