Exports

The BlockList object can be used with some network APIs to specify rules for disabling inbound or outbound access to specific IP addresses, IP ranges, or IP subnets.

@since v15.0.0, v14.18.0

This class is used to create a TCP or IPC server.

@since v0.1.90

This class is used to create a TCP or IPC server.

@since v0.1.90

This class is an abstraction of a TCP socket or a streaming IPC endpoint (uses named pipes on Windows, and Unix domain sockets otherwise). It is also an EventEmitter.

A net.Socket can be created by the user and used directly to interact with a server. For example, it is returned by createConnection, so the user can use it to talk to the server.

It can also be created by Node.js and passed to the user when a connection is received. For example, it is passed to the listeners of a 'connection' event emitted on a Server, so the user can use it to interact with the client.

@since v0.3.4

@since v15.14.0, v14.18.0

Aliases to createConnection.

Possible signatures:

• connect
• connect for IPC connections.
• connect for TCP connections.

Aliases to createConnection.

Possible signatures:

• connect
• connect for IPC connections.
• connect for TCP connections.

Aliases to createConnection.

Possible signatures:

• connect
• connect for IPC connections.
• connect for TCP connections.

A factory function, which creates a new Socket, immediately initiates connection with socket.connect(), then returns the net.Socket that starts the connection.

When the connection is established, a 'connect' event will be emitted on the returned socket. The last parameter connectListener, if supplied, will be added as a listener for the 'connect' event once.

Possible signatures:

• createConnection
• createConnection for IPC connections.
• createConnection for TCP connections.

The connect function is an alias to this function.

A factory function, which creates a new Socket, immediately initiates connection with socket.connect(), then returns the net.Socket that starts the connection.

When the connection is established, a 'connect' event will be emitted on the returned socket. The last parameter connectListener, if supplied, will be added as a listener for the 'connect' event once.

Possible signatures:

• createConnection
• createConnection for IPC connections.
• createConnection for TCP connections.

The connect function is an alias to this function.

A factory function, which creates a new Socket, immediately initiates connection with socket.connect(), then returns the net.Socket that starts the connection.

When the connection is established, a 'connect' event will be emitted on the returned socket. The last parameter connectListener, if supplied, will be added as a listener for the 'connect' event once.

Possible signatures:

• createConnection
• createConnection for IPC connections.
• createConnection for TCP connections.

The connect function is an alias to this function.

Creates a new TCP or IPC server.

If allowHalfOpen is set to true, when the other end of the socket signals the end of transmission, the server will only send back the end of transmission when socket.end() is explicitly called. For example, in the context of TCP, when a FIN packed is received, a FIN packed is sent back only when socket.end() is explicitly called. Until then the connection is half-closed (non-readable but still writable). See 'end' event and RFC 1122 (section 4.2.2.13) for more information.

If pauseOnConnect is set to true, then the socket associated with each incoming connection will be paused, and no data will be read from its handle. This allows connections to be passed between processes without any data being read by the original process. To begin reading data from a paused socket, call socket.resume().

The server can be a TCP server or an IPC server, depending on what it listen() to.

Here is an example of a TCP echo server which listens for connections on port 8124:

import net from 'node:net';
const server = net.createServer((c) => {
// 'connection' listener.
console.log('client connected');
c.on('end', () => {
console.log('client disconnected');
});
c.write('hello\r\n');
c.pipe(c);
});
server.on('error', (err) => {
throw err;
});
server.listen(8124, () => {
console.log('server bound');
});

Test this by using telnet:

telnet localhost 8124

To listen on the socket /tmp/echo.sock:

server.listen('/tmp/echo.sock', () => {
console.log('server bound');
});

Use nc to connect to a Unix domain socket server:

nc -U /tmp/echo.sock

@since v0.5.0

Creates a new TCP or IPC server.

If allowHalfOpen is set to true, when the other end of the socket signals the end of transmission, the server will only send back the end of transmission when socket.end() is explicitly called. For example, in the context of TCP, when a FIN packed is received, a FIN packed is sent back only when socket.end() is explicitly called. Until then the connection is half-closed (non-readable but still writable). See 'end' event and RFC 1122 (section 4.2.2.13) for more information.

If pauseOnConnect is set to true, then the socket associated with each incoming connection will be paused, and no data will be read from its handle. This allows connections to be passed between processes without any data being read by the original process. To begin reading data from a paused socket, call socket.resume().

The server can be a TCP server or an IPC server, depending on what it listen() to.

Here is an example of a TCP echo server which listens for connections on port 8124:

import net from 'node:net';
const server = net.createServer((c) => {
// 'connection' listener.
console.log('client connected');
c.on('end', () => {
console.log('client disconnected');
});
c.write('hello\r\n');
c.pipe(c);
});
server.on('error', (err) => {
throw err;
});
server.listen(8124, () => {
console.log('server bound');
});

Test this by using telnet:

telnet localhost 8124

To listen on the socket /tmp/echo.sock:

server.listen('/tmp/echo.sock', () => {
console.log('server bound');
});

Use nc to connect to a Unix domain socket server:

nc -U /tmp/echo.sock

@since v0.5.0

Gets the current default value of the autoSelectFamily option of socket.connect(options). The initial default value is true, unless the command line option--no-network-family-autoselection is provided.

@since v19.4.0

Gets the current default value of the autoSelectFamilyAttemptTimeout option of socket.connect(options). The initial default value is 250 or the value specified via the command line option --network-family-autoselection-attempt-timeout.

@since v19.8.0, v18.8.0

Returns. The current default value of the autoSelectFamilyAttemptTimeout option.

Returns 6 if input is an IPv6 address. Returns 4 if input is an IPv4 address in dot-decimal notation with no leading zeroes. Otherwise, returns0.

net.isIP('::1'); // returns 6
net.isIP('127.0.0.1'); // returns 4
net.isIP('127.000.000.001'); // returns 0
net.isIP('127.0.0.1/24'); // returns 0
net.isIP('fhqwhgads'); // returns 0

@since v0.3.0

Returns true if input is an IPv4 address in dot-decimal notation with no leading zeroes. Otherwise, returns false.

net.isIPv4('127.0.0.1'); // returns true
net.isIPv4('127.000.000.001'); // returns false
net.isIPv4('127.0.0.1/24'); // returns false
net.isIPv4('fhqwhgads'); // returns false

@since v0.3.0

Returns true if input is an IPv6 address. Otherwise, returns false.

net.isIPv6('::1'); // returns true
net.isIPv6('fhqwhgads'); // returns false

@since v0.3.0

Sets the default value of the autoSelectFamily option of socket.connect(options).

@since v19.4.0

Sets the default value of the autoSelectFamilyAttemptTimeout option of socket.connect(options).

@since v19.8.0, v18.8.0