A host is sending a ping packet to another host in the same subnet.
For which IP address does the sending host perform an ARP broadcast to resolve?
- its own IP address
- the IP address of the router
- the IP address of the DNS server
- the IP address of the destination host
All communication within a subnet is based on MAC addresses. When the destination is in the same subnet, the source device performs an ARP broadcast to learn the MAC address of the destination host.
The Address Resolution Protocol (ARP) is used in TCP/IP to resolve media access control (MAC) addresses to IP addresses. Mac addresses are configured on each NIC on an Ethernet network so that the nodes can be identified on the network. ARP enables the MAC addressing that Ethernet requires to interoperate with the IP addressing that TCP/IP requires. You can use the arp utility to view and manage the ARP cache on a computer. To use the arp utility, you can issue the arp command with various switches at a command prompt. The source device will perform an ARP broadcast to learn the mac address of the router in cases were the destination is in another subnet. Then the router will take over from there.
The source device will never perform an ARP broadcast to learn its own MAC address.
The only time a source device will perform an ARP broadcast to learn the MAC address of the DNS server is when communication is being done by name and not IP address.
Objective: Network Concepts
Sub-Objective: Describe IP subnets and communication within an IP subnet and between IP subnets