In IP networking, besides the IP address, what information is needed to establish communication between hosts?

In IP networking, besides the IP address, what information is needed to establish communication between hosts?

• A. Ports
• B. Subnet mask
• C. DNS name
• D. MAC address

Answer: (A)

When two hosts communicate over IP, you need both the destination IP address and the destination port. The IP address ensures the packet reaches the correct host, while the port identifies which application or service on that host should receive the data. This pairing lets the transport layer (TCP/UDP) demultiplex incoming traffic to the right process, enabling a specific connection or data stream. DNS names are just human-friendly ways to find an IP, so they’re optional if you already have the IP. Subnet masks help determine whether a destination is on the local network, not the actual end-to-end delivery, and MAC addresses are used only on the local link to get frames to the next hop, not for routing across networks.

When two hosts communicate over IP, you need both the destination IP address and the destination port. The IP address ensures the packet reaches the correct host, while the port identifies which application or service on that host should receive the data. This pairing lets the transport layer (TCP/UDP) demultiplex incoming traffic to the right process, enabling a specific connection or data stream. DNS names are just human-friendly ways to find an IP, so they’re optional if you already have the IP. Subnet masks help determine whether a destination is on the local network, not the actual end-to-end delivery, and MAC addresses are used only on the local link to get frames to the next hop, not for routing across networks.