Given that Host A and Host B are in different networks. When Host A is trying to communicate with Host B, which step will Host A take first?
A.
Send a TCP SYN and wait for the SYN ACK with the IP address of Host B
B.
Drop the data.
C.
Create an ARP request to get a MAC address for Host B.
D.
Send the data frames to the default gateway.
Explanation:
This question is to examine the ARP working principle.
When Host A doesn’t know the MAC address of Host B, the ARP request will be broadcast so that all hosts on the LAN can see this request. If the IP is not local, the router will check its routing table to see whether there is a route to the destination network. If there is, the router will reply with its own MAC address.
So C is correct.