Refer to the exhibit.
After HostA pings HostB, which entry will be in the ARP cache of HostA to support this
transmission?
A.
Exhibit A
B.
Exhibit B
C.
Exhibit C
D.
Exhibit D
E.
Exhibit E
F.
Exhibit F
Explanation:
When a host needs to reach a device on another subnet, the ARP cache entry will be that of
the Ethernet address of the local router (default gateway) for the physical MAC address. The
destination IP address will not change, and will be that of the remote host (HostB).
The correct answer is A. In the 200-120 Test bank, A was the selection. For some reason it has changed here.
When going through the network, the MAC address will change at each router, BUT the destination IP will remain the same. Even your explanation states this. Host A will see the MAC address of Router 1, but continue seeing the IP of Host B.
I agree Henry. Is this a typo or am I missing something?
Gotta be a typo
No the answer is D. Host A needs a MAC to send the frame to the RTR. SO it needs the RTR’s MAC from its ARP table.
Yes the RTR;s MAC is also answer A. But the IP must be the end destination so A is correct.
No D is correct
Since Host B is not one the same network as Host A, Host A will default to its default gateway.
To support this transmission the ARP cache will contain,
Interface Address Physical Address dynamic
192.168.6.1 000f.2480.8916
answer is A…When a PC wants to communicate w a PC outside the network, it first sends an ARP with a destination MAC address of FFFF.FFFF.FFFF together with the destination ip address ie 192.168.4.7 and it is this IP address that is associated with the Routers MAC address…
Just test it by yourself. Ping for example 8.8.8.8 and check which entry is in the ARP table (cmd -> arp -a). Should be the IP and MAC address of your router. So answer D is correct.
I think the “trick” in this question is that it allows you to confuse yourself with the destination IP addresses of the PACKET vs. the destination IP in the ARP CACHE.
Host A only ever learns one way to get outside of its own network and that is through the default gateway. So, following logical reasoning, the ARP cache of Host A would only have …
Destination IP = 192.168.6.1
Destination MAC = 000f.2480.8916
… in its table for anything that is not in the 192.168.6.x network (assuming a default gateway is configured on the Host and the ARP resolution has already taken place that associates 192.168.6.1 to 000f.2480.8916). The ARP cache saves having to do a broadcast ARP request every time Host A has to figure out where to send a PACKET with a destination outside of its own network.
Damn tricky question for those of us just starting out because we also learn that source IP and destination IP do not change during transit. However, if you read the question literally, I think the answer is D – given that the question asks what will be in the ARP CACHE and not in the PACKET coming from Host A.
I aggree with you Craig. Thanks for the explanation.
The first question explains what is happening after, what the router will do with it.
http://www.aiotestking.com/cisco/what-will-router1-do-when-it-receives-the-data-frame-shown-6/