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.

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

> [!WARNING] Deno compatibility > The `fd` option is not supported. 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](.././node__net.d.ts/~/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](.././node__net.d.ts/~/Server), so the user can use it to interact with the client.

Aliases to [createConnection](.././node__net.d.ts/~/createConnection). Possible signatures: * [connect](.././node__net.d.ts/~/connect) * [connect](.././node__net.d.ts/~/connect) for `IPC` connections. * [connect](.././node__net.d.ts/~/connect) for TCP connections.

A factory function, which creates a new [Socket](.././node__net.d.ts/~/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](.././node__net.d.ts/~/createConnection) * [createConnection](.././node__net.d.ts/~/createConnection) for `IPC` connections. * [createConnection](.././node__net.d.ts/~/createConnection) for TCP connections. The [connect](.././node__net.d.ts/~/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](https://tools.ietf.org/html/rfc1122) (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: ```js 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`: ```bash telnet localhost 8124 ``` To listen on the socket `/tmp/echo.sock`: ```js server.listen('/tmp/echo.sock', () => { console.log('server bound'); }); ``` Use `nc` to connect to a Unix domain socket server: ```bash nc -U /tmp/echo.sock ```

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.

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`.

Returns `6` if `input` is an IPv6 address. Returns `4` if `input` is an IPv4 address in [dot-decimal notation](https://en.wikipedia.org/wiki/Dot-decimal_notation) with no leading zeroes. Otherwise, returns`0`. ```js 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 ```

Returns `true` if `input` is an IPv4 address in [dot-decimal notation](https://en.wikipedia.org/wiki/Dot-decimal_notation) with no leading zeroes. Otherwise, returns `false`. ```js 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 ```

Returns `true` if `input` is an IPv6 address. Otherwise, returns `false`. ```js net.isIPv6('::1'); // returns true net.isIPv6('fhqwhgads'); // returns false ```

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

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