//tag::ref-doc[]
= TCP
The `tcp` source acts as a server and allows a remote party to connect to it and submit data over a raw tcp socket.
TCP is a streaming protocol and some mechanism is needed to frame messages on the wire. A number of decoders are
available, the default being 'CRLF' which is compatible with Telnet.
Messages produced by the TCP source application have a `byte[]` payload.
== Options
//tag::configuration-properties[]
Properties grouped by prefix:
=== tcp
$$nio$$:: $$Whether or not to use NIO.$$ *($$Boolean$$, default: `$$false$$`)*
$$port$$:: $$The port on which to listen; 0 for the OS to choose a port.$$ *($$Integer$$, default: `$$1234$$`)*
$$reverse-lookup$$:: $$Perform a reverse DNS lookup on the remote IP Address; if false, just the IP address is included in the message headers.$$ *($$Boolean$$, default: `$$false$$`)*
$$socket-timeout$$:: $$The timeout (ms) before closing the socket when no data is received.$$ *($$Integer$$, default: `$$120000$$`)*
$$use-direct-buffers$$:: $$Whether or not to use direct buffers.$$ *($$Boolean$$, default: `$$false$$`)*
=== tcp.supplier
$$buffer-size$$:: $$The buffer size used when decoding messages; larger messages will be rejected.$$ *($$Integer$$, default: `$$2048$$`)*
$$decoder$$:: $$The decoder to use when receiving messages.$$ *($$Encoding$$, default: `$$<none>$$`, possible values: `CRLF`,`LF`,`NULL`,`STXETX`,`RAW`,`L1`,`L2`,`L4`)*
//end::configuration-properties[]
== Available Decoders
.Text Data
CRLF (default):: text terminated by carriage return (0x0d) followed by line feed (0x0a)
LF:: text terminated by line feed (0x0a)
NULL:: text terminated by a null byte (0x00)
STXETX:: text preceded by an STX (0x02) and terminated by an ETX (0x03)
.Text and Binary Data
RAW:: no structure - the client indicates a complete message by closing the socket
L1:: data preceded by a one byte (unsigned) length field (supports up to 255 bytes)
L2:: data preceded by a two byte (unsigned) length field (up to 2^16^-1 bytes)
L4:: data preceded by a four byte (signed) length field (up to 2^31^-1 bytes)
//end::ref-doc[]
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