Raw sockets work by allowing applications to bypass the standard transport layer protocols (like TCP and UDP) and directly interact with the network layer. Here's how they function:
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Socket Creation: An application creates a raw socket using system calls (e.g.,
socket()in C) with a specific protocol type, such asIPPROTO_RAW. -
Packet Crafting: The application constructs the entire packet, including headers and payload. This includes specifying the IP header, transport layer headers, and any application data.
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Sending Packets: The application sends the crafted packet using the
sendto()function. The operating system then transmits the packet over the network. -
Receiving Packets: The application can also receive packets using the
recvfrom()function. It can capture all incoming packets, regardless of their protocol, allowing for detailed analysis. -
Bypassing Protocol Stack: Since raw sockets operate at a lower level, they can manipulate packet headers and contents directly, which is not possible with standard sockets.
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Privileges: Raw sockets typically require elevated privileges (like root access) to prevent misuse, as they can be used to create malicious traffic.
This low-level access enables a wide range of applications, from network diagnostics to security testing.
