200-125 question 22 discussion


Refer to the exhibit:

What will Router1 do when it receives the data frame shown? (Choose three.)

  • A. Router1 will strip off the source MAC address and replace it with the MAC address 0000.0c36.6965.
  • B. Router1 will strip off the source IP address and replace it with the IP address
  • C. Router1 will strip off the destination MAC address and replace it with the MAC address 0000.0c07.4320.
  • D. Router1 will strip off the destination IP address and replace it with the IP address of
  • E. Router1 will forward the data packet out interface FastEthernet0/1.
  • F. Router1 will forward the data packet out interface FastEthernet0/2.
Created 5 months ago by GiKi72


I think true answer for this question are A,C,E???


no , right answer is f bcz mac add 0000.0c07.4320 belongs on f0/2


it is A C F the only mac addresses change. the interfaces directly connected to the router have age(min) instead they have "-" so the mac address of interface fa0/2 is 0000.0c36.6965 which is the source MAC address and 0000.0c07.4320 is the destination address


no its F because int fa0/2 has the mac address 0000.0c36.6965.


The correct answer is ACF. Note that fa0/1 will deliver the packet to subnet, which is not same as the destination of the frame.


I get C and F, but why A?


I had to really sit here and break it down, but if finally makes sense to me. 1. The data frame the router received came from with source MAC address of 0000.0c07.f892. 2. In order for this packet to reach its destination of, the router will have to route this packet out its interface, hence the reason the data frame has 0000.0c63.ae45 as the destination MAC (can't use MAC addresses belonging to hosts in another subnet). 3. The router then uses the interface that is connected to the same subnet as your destination IP address. 4. The router will send the frame out with its source IP address and source MAC address of 0000.0c36.6965 (hence the reason why A is part of the answer) out to destination IP and destination MAC 0000.0c07.4320 (hence why C is also a part of the answer). 5. Last, we look at the ARP table to see what interface is on . It says FastEthernet 0/2. (Answer F).


Correct answer is ACF Here is the explanation 1. Look at arp table. Wherever you see hyphen (-), those are Router1 interfaces. If you look at destination Mac address of the Data Frame received, you will conclude that frame has been received on f0/0 of the router1( It is received from ( source mac address of 0000.0c07.f892) because both are on the same subnet 2. Destination IP address in the Frame tells you that it is being destined to subnet. 3. Again look at ARP table, you will see interface f0/2 ( of router1 is in the same subnet I,e, so frame will get processed and get out of the router1 through interface f0/2- This explains answer F 4. Since frame is getting out of f0/2, the source mac address of processed frame will be the mac address of f0/2 of the router1 i,e 0000.0c36.6965. This explains answer A. 5. Since mac 0000.0c07.4320 corresponds to final destination ip hence the answer C


A, D, E the procedures


a c f