socat – multipurpose relay (SOcket CAT)

socat is a flexible, multi-purpose relay tool. Its purpose is to establish a relationship between two data sources, where each data source can be a file, a Unix socket, UDP, TCP, or standard input.

This command line based utility that establishes two bidirectional byte streams and transfers
data between them. Because the streams can be constructed from a large set of different types of data sinks and sources (see address types), and because lots of address options may be applied to the streams, socat can be used for many different purposes.

This is free and open source software.

Features include:

  • Many different types of channels socat can connect, including:
    • Files.
    • Pipes.
    • Devices (serial line, pseudo-terminal, etc).
    • Sockets (UNIX, IP4, IP6 – raw, UDP, TCP).
    • SSL sockets.
    • Proxy CONNECT connections.
    • File descriptors (stdin, etc).
    • The GNU line editor (readline).
    • Programs.
    • Combinations of two of these.
  • TCP port forwarder (one-shot or daemon).
    • External socksifier.
    • Tool to attack weak firewalls (security and audit).
    • Shell interface to Unix sockets.
    • IP6 relay.
    • Redirect TCP-oriented programs to a serial line.
    • Logically connect serial lines on different computers.
    • Establish a relatively secure environment (su and chroot) for running client or server shell scripts with network connections.
  • Regarded as the advanced version of netcat.

Developer: Gerhard Rieger
License: GNU General Public License v2.0

socat is written in C. Learn C with our recommended free books and free tutorials.

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