lähdeMACosoite

LähdeMACosoite, often translated as "source MAC address," is a field within the header of an Ethernet frame. It specifies the physical hardware address of the network interface card (NIC) that originated the frame. MAC addresses are unique identifiers assigned to network interfaces by their manufacturers.

The source MAC address is crucial for local network communication. When a device sends a data frame, it includes its own MAC address in the source field. This allows other devices on the same local network segment to identify the sender. It is also used by switches to build their forwarding tables, which map MAC addresses to specific ports, enabling efficient delivery of frames to their intended recipients.

In contrast to IP addresses, which are logical and can change, MAC addresses are typically permanent and hardcoded into the network interface hardware. While it's possible to spoof a MAC address, its primary purpose is to identify the physical origin of a network packet within a local broadcast domain. The source MAC address is distinct from the destination MAC address, which indicates the intended recipient of the frame on the local network. Without the source MAC address, it would be difficult for network devices to track the origin of data and manage traffic flow effectively at the data link layer.