What is packet header?

A packet header is a section of data that precedes the actual payload in a network packet, containing crucial information for routing and delivering the packet across networks. It typically includes details such as source and destination IP addresses, protocol type, packet size, and sequence numbers. This information helps networking devices, like routers and switches, make informed decisions about how to handle and forward the packet. The structure and content of packet headers vary depending on the underlying communication protocol, such as TCP/IP or UDP.