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.changelog > summary {
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"> <link rel="stylesheet" href="data:text/css;base64,LnNoX3NvdXJjZUNvZGUgewogIGZvbnQtd2VpZ2h0OiBub3JtYWw7CiAgZm9udC1zdHlsZTogbm9ybWFsOwp9Cgouc2hfc291cmNlQ29kZSAuc2hfc3ltYm9sLAouc2hfc291cmNlQ29kZSAuc2hfY2JyYWNrZXQgewogIGNvbG9yOiAjMzMzOwp9Cgouc2hfc291cmNlQ29kZSAuc2hfa2V5d29yZCB7CiAgY29sb3I6ICMzMzg7Cn0KCi5zaF9zb3VyY2VDb2RlIC5zaF9zdHJpbmcsCi5zaF9zb3VyY2VDb2RlIC5zaF9yZWdleHAsCi5zaF9zb3VyY2VDb2RlIC5zaF9udW1iZXIsCi5zaF9zb3VyY2VDb2RlIC5zaF9zcGVjaWFsY2hhciB7CiAgY29sb3I6ICNFNTQzMDU7Cn0KCi5zaF9zb3VyY2VDb2RlIC5zaF9jb21tZW50IHsKICBjb2xvcjogIzY2NjsKICBmb250LXdlaWdodDogbGlnaHRlcjsKfQo="> <link rel="canonical" href="https://nodejs.org/api/net.html"> </head> <body class="alt apidoc" id="api-section-net"> <div id="content" class="clearfix"> <div id="column2" class="interior"> <div id="intro" class="interior"> <a href="https://nodejs.org/" title="Go back to the home page"> Node.js </a> </div> <ul> <li><a href="https://nodejs.org/api/documentation.html" class="nav-documentation">About these Docs</a></li> 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<ul> <li><a href="#net_new_net_server_options_connectionlistener">new net.Server([options][, connectionListener])</a></li> <li><a href="#net_event_close">Event: 'close'</a></li> <li><a href="#net_event_connection">Event: 'connection'</a></li> <li><a href="#net_event_error">Event: 'error'</a></li> <li><a href="#net_event_listening">Event: 'listening'</a></li> <li><a href="#net_server_address">server.address()</a></li> <li><a href="#net_server_close_callback">server.close([callback])</a></li> <li><span class="stability_0"><a href="#net_server_connections">server.connections</a></span></li> <li><a href="#net_server_getconnections_callback">server.getConnections(callback)</a></li> <li> <p><a href="#net_server_listen">server.listen()</a></p> <ul> <li><a href="#net_server_listen_handle_backlog_callback">server.listen(handle[, backlog][, callback])</a></li> <li><a href="#net_server_listen_options_callback">server.listen(options[, callback])</a></li> <li><a href="#net_server_listen_path_backlog_callback">server.listen(path[, backlog][, callback])</a></li> <li><a href="#net_server_listen_port_host_backlog_callback">server.listen([port[, host[, backlog]]][, callback])</a></li> </ul> </li> <li><a href="#net_server_listening">server.listening</a></li> <li><a href="#net_server_maxconnections">server.maxConnections</a></li> <li><a href="#net_server_ref">server.ref()</a></li> <li><a href="#net_server_unref">server.unref()</a></li> </ul> </li> <li> <p><a href="#net_class_net_socket">Class: net.Socket</a></p> <ul> <li><a href="#net_new_net_socket_options">new net.Socket([options])</a></li> <li><a href="#net_event_close_1">Event: 'close'</a></li> <li><a href="#net_event_connect">Event: 'connect'</a></li> <li><a href="#net_event_data">Event: 'data'</a></li> <li><a href="#net_event_drain">Event: 'drain'</a></li> <li><a href="#net_event_end">Event: 'end'</a></li> <li><a href="#net_event_error_1">Event: 'error'</a></li> <li><a href="#net_event_lookup">Event: 'lookup'</a></li> <li><a href="#net_event_ready">Event: 'ready'</a></li> <li><a href="#net_event_timeout">Event: 'timeout'</a></li> <li><a href="#net_socket_address">socket.address()</a></li> <li><a href="#net_socket_buffersize">socket.bufferSize</a></li> <li><a href="#net_socket_bytesread">socket.bytesRead</a></li> <li><a href="#net_socket_byteswritten">socket.bytesWritten</a></li> <li> <p><a href="#net_socket_connect">socket.connect()</a></p> <ul> <li><a href="#net_socket_connect_options_connectlistener">socket.connect(options[, connectListener])</a></li> <li><a href="#net_socket_connect_path_connectlistener">socket.connect(path[, connectListener])</a></li> <li><a href="#net_socket_connect_port_host_connectlistener">socket.connect(port[, host][, connectListener])</a></li> </ul> </li> <li><a href="#net_socket_connecting">socket.connecting</a></li> <li><a href="#net_socket_destroy_exception">socket.destroy([exception])</a></li> <li><a href="#net_socket_destroyed">socket.destroyed</a></li> <li><a href="#net_socket_end_data_encoding_callback">socket.end([data][, encoding][, callback])</a></li> <li><a href="#net_socket_localaddress">socket.localAddress</a></li> <li><a href="#net_socket_localport">socket.localPort</a></li> <li><a href="#net_socket_pause">socket.pause()</a></li> <li><a href="#net_socket_pending">socket.pending</a></li> <li><a href="#net_socket_ref">socket.ref()</a></li> <li><a href="#net_socket_remoteaddress">socket.remoteAddress</a></li> <li><a href="#net_socket_remotefamily">socket.remoteFamily</a></li> <li><a href="#net_socket_remoteport">socket.remotePort</a></li> <li><a href="#net_socket_resume">socket.resume()</a></li> <li><a href="#net_socket_setencoding_encoding">socket.setEncoding([encoding])</a></li> <li><a href="#net_socket_setkeepalive_enable_initialdelay">socket.setKeepAlive([enable][, initialDelay])</a></li> <li><a href="#net_socket_setnodelay_nodelay">socket.setNoDelay([noDelay])</a></li> <li><a href="#net_socket_settimeout_timeout_callback">socket.setTimeout(timeout[, callback])</a></li> <li><a href="#net_socket_unref">socket.unref()</a></li> <li><a href="#net_socket_write_data_encoding_callback">socket.write(data[, encoding][, callback])</a></li> </ul> </li> <li> <p><a href="#net_net_connect">net.connect()</a></p> <ul> <li><a href="#net_net_connect_options_connectlistener">net.connect(options[, connectListener])</a></li> <li><a href="#net_net_connect_path_connectlistener">net.connect(path[, connectListener])</a></li> <li><a href="#net_net_connect_port_host_connectlistener">net.connect(port[, host][, connectListener])</a></li> </ul> </li> <li> <p><a href="#net_net_createconnection">net.createConnection()</a></p> <ul> <li><a href="#net_net_createconnection_options_connectlistener">net.createConnection(options[, connectListener])</a></li> <li><a href="#net_net_createconnection_path_connectlistener">net.createConnection(path[, connectListener])</a></li> <li><a href="#net_net_createconnection_port_host_connectlistener">net.createConnection(port[, host][, connectListener])</a></li> </ul> </li> <li><a href="#net_net_createserver_options_connectionlistener">net.createServer([options][, connectionListener])</a></li> <li><a href="#net_net_isip_input">net.isIP(input)</a></li> <li><a href="#net_net_isipv4_input">net.isIPv4(input)</a></li> <li><a href="#net_net_isipv6_input">net.isIPv6(input)</a></li> </ul> </li> </ul> </div> <div id="apicontent"> <h1>Net<span><a class="mark" href="#net_net" id="net_net">#</a></span></h1>  <p></p><div class="api_stability api_stability_2"><a href="https://nodejs.org/api/documentation.html#documentation_stability_index">Stability: 2</a> - Stable</div><p></p> <p>The <code>net</code> module provides an asynchronous network API for creating stream-based TCP or <a href="#net_ipc_support">IPC</a> servers (<a href="#net_net_createserver_options_connectionlistener"><code>net.createServer()</code></a>) and clients (<a href="#net_net_createconnection"><code>net.createConnection()</code></a>).</p> <p>It can be accessed using:</p> <pre><code class="language-js">const net = require('net'); </code></pre> <h2>IPC Support<span><a class="mark" href="#net_ipc_support" id="net_ipc_support">#</a></span></h2> <p>The <code>net</code> module supports IPC with named pipes on Windows, and Unix domain sockets on other operating systems.</p> <h3>Identifying paths for IPC connections<span><a class="mark" href="#net_identifying_paths_for_ipc_connections" id="net_identifying_paths_for_ipc_connections">#</a></span></h3> <p><a href="#net_net_connect"><code>net.connect()</code></a>, <a href="#net_net_createconnection"><code>net.createConnection()</code></a>, <a href="#net_server_listen"><code>server.listen()</code></a> and <a href="#net_socket_connect"><code>socket.connect()</code></a> take a <code>path</code> parameter to identify IPC endpoints.</p> <p>On Unix, the local domain is also known as the Unix domain. The path is a filesystem pathname. It gets truncated to <code>sizeof(sockaddr_un.sun_path) - 1</code>, which varies on different operating system between 91 and 107 bytes. The typical values are 107 on Linux and 103 on macOS. The path is subject to the same naming conventions and permissions checks as would be done on file creation. If the Unix domain socket (that is visible as a file system path) is created and used in conjunction with one of Node.js' API abstractions such as <a href="#net_net_createserver_options_connectionlistener"><code>net.createServer()</code></a>, it will be unlinked as part of <a href="#net_server_close_callback"><code>server.close()</code></a>. On the other hand, if it is created and used outside of these abstractions, the user will need to manually remove it. The same applies when the path was created by a Node.js API but the program crashes abruptly. In short, a Unix domain socket once successfully created will be visible in the filesystem, and will persist until unlinked.</p> <p>On Windows, the local domain is implemented using a named pipe. The path <em>must</em> refer to an entry in <code>\\?\pipe\</code> or <code>\\.\pipe\</code>. Any characters are permitted, but the latter may do some processing of pipe names, such as resolving <code>..</code> sequences. Despite how it might look, the pipe namespace is flat. Pipes will <em>not persist</em>. They are removed when the last reference to them is closed. Unlike Unix domain sockets, Windows will close and remove the pipe when the owning process exits.</p> <p>JavaScript string escaping requires paths to be specified with extra backslash escaping such as:</p> <pre><code class="language-js">net.createServer().listen( path.join('\\\\?\\pipe', process.cwd(), 'myctl')); </code></pre> <h2>Class: net.Server<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1140">[src]</a><span><a class="mark" href="#net_class_net_server" id="net_class_net_server">#</a></span></h2> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li>Extends: <a href="https://nodejs.org/api/events.html#events_class_eventemitter" class="type"><EventEmitter></a></li> </ul> <p>This class is used to create a TCP or <a href="#net_ipc_support">IPC</a> server.</p> <h3>new net.Server([options][, connectionlistener])<span><a class="mark" href="#net_new_net_server_options_connectionlistener" id="net_new_net_server_options_connectionlistener">#</a></span></h3> <ul> <li><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> See <a href="#net_net_createserver_options_connectionlistener"><code>net.createServer([options][, connectionListener])</code></a>.</li> <li><code>connectionListener</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Automatically set as a listener for the <a href="#net_event_connection"><code>'connection'</code></a> event.</li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p><code>net.Server</code> is an <a href="https://nodejs.org/api/events.html#events_class_eventemitter"><code>EventEmitter</code></a> with the following events:</p> <h3>Event: 'close'<span><a class="mark" href="#net_event_close" id="net_event_close">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.5.0</span> </div> <p>Emitted when the server closes. If connections exist, this event is not emitted until all connections are ended.</p> <h3>Event: 'connection'<span><a class="mark" href="#net_event_connection" id="net_event_connection">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li><a href="https://nodejs.org/api/net.html#net_class_net_socket" class="type"><net.Socket></a> The connection object</li> </ul> <p>Emitted when a new connection is made. <code>socket</code> is an instance of <code>net.Socket</code>.</p> <h3>Event: 'error'<span><a class="mark" href="#net_event_error" id="net_event_error">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Error" class="type"><Error></a></li> </ul> <p>Emitted when an error occurs. Unlike <a href="#net_class_net_socket"><code>net.Socket</code></a>, the <a href="#net_event_close"><code>'close'</code></a> event will <strong>not</strong> be emitted directly following this event unless <a href="#net_server_close_callback"><code>server.close()</code></a> is manually called. See the example in discussion of <a href="#net_server_listen"><code>server.listen()</code></a>.</p> <h3>Event: 'listening'<span><a class="mark" href="#net_event_listening" id="net_event_listening">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <p>Emitted when the server has been bound after calling <a href="#net_server_listen"><code>server.listen()</code></a>.</p> <h3>server.address()<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1499">[src]</a><span><a class="mark" href="#net_server_address" id="net_server_address">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li>Returns: <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> | <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> </ul> <p>Returns the bound <code>address</code>, the address <code>family</code> name, and <code>port</code> of the server as reported by the operating system if listening on an IP socket (useful to find which port was assigned when getting an OS-assigned address): <code>{ port: 12346, family: 'IPv4', address: '127.0.0.1' }</code>.</p> <p>For a server listening on a pipe or Unix domain socket, the name is returned as a string.</p> <pre><code class="language-js">const server = net.createServer((socket) => { socket.end('goodbye\n'); }).on('error', (err) => { // handle errors here throw err; }); // Grab an arbitrary unused port. server.listen(() => { console.log('opened server on', server.address()); }); </code></pre> <p>Don't call <code>server.address()</code> until the <code>'listening'</code> event has been emitted.</p> <h3>server.close([callback])<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1585">[src]</a><span><a class="mark" href="#net_server_close_callback" id="net_server_close_callback">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Called when the server is closed</li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p>Stops the server from accepting new connections and keeps existing connections. This function is asynchronous, the server is finally closed when all connections are ended and the server emits a <a href="#net_event_close"><code>'close'</code></a> event. The optional <code>callback</code> will be called once the <code>'close'</code> event occurs. Unlike that event, it will be called with an <code>Error</code> as its only argument if the server was not open when it was closed.</p> <h3>server.connections<span><a class="mark" href="#net_server_connections" id="net_server_connections">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.2.0</span><span>Deprecated since: v0.9.7</span> </div> <p></p><div class="api_stability api_stability_0"><a href="https://nodejs.org/api/documentation.html#documentation_stability_index">Stability: 0</a> - Deprecated: Use <a href="#net_server_getconnections_callback"><code>server.getConnections()</code></a> instead.</div><p></p> <p>The number of concurrent connections on the server.</p> <p>This becomes <code>null</code> when sending a socket to a child with <a href="https://nodejs.org/api/child_process.html#child_process_child_process_fork_modulepath_args_options"><code>child_process.fork()</code></a>. To poll forks and get current number of active connections, use asynchronous <a href="#net_server_getconnections_callback"><code>server.getConnections()</code></a> instead.</p> <h3>server.getConnections(callback)<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1547">[src]</a><span><a class="mark" href="#net_server_getconnections_callback" id="net_server_getconnections_callback">#</a></span></h3> <div class="api_metadata"> <span>Added in: v0.9.7</span> </div> <ul> <li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a></li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p>Asynchronously get the number of concurrent connections on the server. Works when sockets were sent to forks.</p> <p>Callback should take two arguments <code>err</code> and <code>count</code>.</p> <h3>server.listen()<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1378">[src]</a><span><a class="mark" href="#net_server_listen" id="net_server_listen">#</a></span></h3> <p>Start a server listening for connections. A <code>net.Server</code> can be a TCP or an <a href="#net_ipc_support">IPC</a> server depending on what it listens to.</p> <p>Possible signatures:</p> <ul> <li><a href="#net_server_listen_handle_backlog_callback"><code>server.listen(handle[, backlog][, callback])</code></a></li> <li><a href="#net_server_listen_options_callback"><code>server.listen(options[, callback])</code></a></li> <li><a href="#net_server_listen_path_backlog_callback"><code>server.listen(path[, backlog][, callback])</code></a> for <a href="#net_ipc_support">IPC</a> servers</li> <li> <a href="#net_server_listen_port_host_backlog_callback"> <code>server.listen([port[, host[, backlog]]][, callback])</code></a> for TCP servers </li> </ul> <p>This function is asynchronous. When the server starts listening, the <a href="#net_event_listening"><code>'listening'</code></a> event will be emitted. The last parameter <code>callback</code> will be added as a listener for the <a href="#net_event_listening"><code>'listening'</code></a> event.</p> <p>All <code>listen()</code> methods can take a <code>backlog</code> parameter to specify the maximum length of the queue of pending connections. The actual length will be determined by the OS through sysctl settings such as <code>tcp_max_syn_backlog</code> and <code>somaxconn</code> on Linux. The default value of this parameter is 511 (not 512).</p> <p>All <a href="#net_class_net_socket"><code>net.Socket</code></a> are set to <code>SO_REUSEADDR</code> (see <a href="http://man7.org/linux/man-pages/man7/socket.7.html"><code>socket(7)</code></a> for details).</p> <p>The <code>server.listen()</code> method can be called again if and only if there was an error during the first <code>server.listen()</code> call or <code>server.close()</code> has been called. Otherwise, an <code>ERR_SERVER_ALREADY_LISTEN</code> error will be thrown.</p> <p>One of the most common errors raised when listening is <code>EADDRINUSE</code>. This happens when another server is already listening on the requested <code>port</code>/<code>path</code>/<code>handle</code>. One way to handle this would be to retry after a certain amount of time:</p> <pre><code class="language-js">server.on('error', (e) => { if (e.code === 'EADDRINUSE') { console.log('Address in use, retrying...'); setTimeout(() => { server.close(); server.listen(PORT, HOST); }, 1000); } }); </code></pre> <h4>server.listen(handle[, backlog][, callback])<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1378">[src]</a><span><a class="mark" href="#net_server_listen_handle_backlog_callback" id="net_server_listen_handle_backlog_callback">#</a></span></h4> <div class="api_metadata"> <span>Added in: v0.5.10</span> </div> <ul> <li><code>handle</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a></li> <li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions</li> <li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions</li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p>Start a server listening for connections on a given <code>handle</code> that has already been bound to a port, a Unix domain socket, or a Windows named pipe.</p> <p>The <code>handle</code> object can be either a server, a socket (anything with an underlying <code>_handle</code> member), or an object with an <code>fd</code> member that is a valid file descriptor.</p> <p>Listening on a file descriptor is not supported on Windows.</p> <h4>server.listen(options[, callback])<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1378">[src]</a><span><a class="mark" href="#net_server_listen_options_callback" id="net_server_listen_options_callback">#</a></span></h4> <div class="api_metadata"> <details class="changelog"><summary>History</summary> <table> <tbody><tr><th>Version</th><th>Changes</th></tr> <tr><td>v11.4.0</td> <td><p>The <code>ipv6Only</code> option is supported.</p></td></tr> <tr><td>v0.11.14</td> <td><p><span>Added in: v0.11.14</span></p></td></tr> </tbody></table> </details> </div> <ul> <li> <p><code>options</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object" class="type"><Object></a> Required. Supports the following properties:</p> <ul> <li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> <li><code>host</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a></li> <li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Will be ignored if <code>port</code> is specified. See <a href="#net_identifying_paths_for_ipc_connections">Identifying paths for IPC connections</a>.</li> <li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions.</li> <li><code>exclusive</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> <strong>Default:</strong> <code>false</code></li> <li><code>readableAll</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For IPC servers makes the pipe readable for all users. <strong>Default:</strong> <code>false</code></li> <li><code>writableAll</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For IPC servers makes the pipe writable for all users. <strong>Default:</strong> <code>false</code></li> <li><code>ipv6Only</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Boolean_type" class="type"><boolean></a> For TCP servers, setting <code>ipv6Only</code> to <code>true</code> will disable dual-stack support, i.e., binding to host <code>::</code> won't make <code>0.0.0.0</code> be bound. <strong>Default:</strong> <code>false</code>.</li> </ul> </li> <li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions.</li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p>If <code>port</code> is specified, it behaves the same as <a href="#net_server_listen_port_host_backlog_callback"> <code>server.listen([port[, host[, backlog]]][, callback])</code></a>. Otherwise, if <code>path</code> is specified, it behaves the same as <a href="#net_server_listen_path_backlog_callback"><code>server.listen(path[, backlog][, callback])</code></a>. If none of them is specified, an error will be thrown.</p> <p>If <code>exclusive</code> is <code>false</code> (default), then cluster workers will use the same underlying handle, allowing connection handling duties to be shared. When <code>exclusive</code> is <code>true</code>, the handle is not shared, and attempted port sharing results in an error. An example which listens on an exclusive port is shown below.</p> <pre><code class="language-js">server.listen({ host: 'localhost', port: 80, exclusive: true }); </code></pre> <p>Starting an IPC server as root may cause the server path to be inaccessible for unprivileged users. Using <code>readableAll</code> and <code>writableAll</code> will make the server accessible for all users.</p> <h4>server.listen(path[, backlog][, callback])<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1378">[src]</a><span><a class="mark" href="#net_server_listen_path_backlog_callback" id="net_server_listen_path_backlog_callback">#</a></span></h4> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li><code>path</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type" class="type"><string></a> Path the server should listen to. See <a href="#net_identifying_paths_for_ipc_connections">Identifying paths for IPC connections</a>.</li> <li><code>backlog</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions.</li> <li><code>callback</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function" class="type"><Function></a> Common parameter of <a href="#net_server_listen"><code>server.listen()</code></a> functions.</li> <li>Returns: <a href="https://nodejs.org/api/net.html#net_class_net_server" class="type"><net.Server></a></li> </ul> <p>Start an <a href="#net_ipc_support">IPC</a> server listening for connections on the given <code>path</code>.</p> <h4>server.listen([port[, host[, backlog]]][, callback])<a class="srclink" href="https://github.com/nodejs/node/blob/3a2e75d9a5c31d20e429d505b82dd182e33f459a/lib/net.js#L1378">[src]</a><span><a class="mark" href="#net_server_listen_port_host_backlog_callback" id="net_server_listen_port_host_backlog_callback">#</a></span></h4> <div class="api_metadata"> <span>Added in: v0.1.90</span> </div> <ul> <li><code>port</code> <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#Number_type" class="type"><number></a></li> <li><code>host</code> <a href="https: