调用ifconfig是非常依赖于平台的，而且网络层知道套接字所在的IP地址，所以最好是询问它。

Node.js并没有公开这样做的直接方法，但是你可以打开任何套接字，并询问正在使用的本地IP地址。例如，打开www.google.com的套接字:

var net = require('net');
function getNetworkIP(callback) {
  var socket = net.createConnection(80, 'www.google.com');
  socket.on('connect', function() {
    callback(undefined, socket.address().address);
    socket.end();
  });
  socket.on('error', function(e) {
    callback(e, 'error');
  });
}

使用情况:

getNetworkIP(function (error, ip) {
    console.log(ip);
    if (error) {
        console.log('error:', error);
    }
});

很多时候，我发现有多个内部和外部面向接口可用(例如:10.0.75.1,172.100.0.1,192.168.2.3)，而我真正想要的是外部接口(172.100.0.1)。

如果其他人也有类似的担忧，这里还有一个关于这个问题的看法，希望能有所帮助……

const address = Object.keys(os.networkInterfaces())
    // flatten interfaces to an array
    .reduce((a, key) => [
        ...a,
        ...os.networkInterfaces()[key]
    ], [])
    // non-internal ipv4 addresses only
    .filter(iface => iface.family === 'IPv4' && !iface.internal)
    // project ipv4 address as a 32-bit number (n)
    .map(iface => ({...iface, n: (d => ((((((+d[0])*256)+(+d[1]))*256)+(+d[2]))*256)+(+d[3]))(iface.address.split('.'))}))
    // set a hi-bit on (n) for reserved addresses so they will sort to the bottom
    .map(iface => iface.address.startsWith('10.') || iface.address.startsWith('192.') ? {...iface, n: Math.pow(2,32) + iface.n} : iface)
    // sort ascending on (n)
    .sort((a, b) => a.n - b.n)
    [0]||{}.address;

下面是前面例子的一个变种。它会小心过滤掉VMware接口等。如果你不传递索引，它会返回所有地址。否则，您可能希望将其默认值设置为0，然后传递null以获取所有值，但您将整理这些。如果想要添加的话，还可以为regex过滤器传入另一个参数。

function getAddress(idx) {

    var addresses = [],
        interfaces = os.networkInterfaces(),
        name, ifaces, iface;

    for (name in interfaces) {
        if(interfaces.hasOwnProperty(name)){
            ifaces = interfaces[name];
            if(!/(loopback|vmware|internal)/gi.test(name)){
                for (var i = 0; i < ifaces.length; i++) {
                    iface = ifaces[i];
                    if (iface.family === 'IPv4' &&  !iface.internal && iface.address !== '127.0.0.1') {
                        addresses.push(iface.address);
                    }
                }
            }
        }
    }

    // If an index is passed only return it.
    if(idx >= 0)
        return addresses[idx];
    return addresses;
}

var ip = req.headers['x-forwarded-for'] || req.socket.remoteAddress 

这些信息可以在os.networkInterfaces()中找到，这是一个对象，它将网络接口名称映射到它的属性(例如，一个接口可以有几个地址):

'use strict';

const { networkInterfaces } = require('os');

const nets = networkInterfaces();
const results = Object.create(null); // Or just '{}', an empty object

for (const name of Object.keys(nets)) {
    for (const net of nets[name]) {
        // Skip over non-IPv4 and internal (i.e. 127.0.0.1) addresses
        // 'IPv4' is in Node <= 17, from 18 it's a number 4 or 6
        const familyV4Value = typeof net.family === 'string' ? 'IPv4' : 4
        if (net.family === familyV4Value && !net.internal) {
            if (!results[name]) {
                results[name] = [];
            }
            results[name].push(net.address);
        }
    }
}

// 'results'
{
  "en0": [
    "192.168.1.101"
  ],
  "eth0": [
    "10.0.0.101"
  ],
  "<network name>": [
    "<ip>",
    "<ip alias>",
    "<ip alias>",
    ...
  ]
}

// results["en0"][0]
"192.168.1.101"

对于Underscore.js和Lodash，正确的一行代码是:

var ip = require('underscore')
    .chain(require('os').networkInterfaces())
    .values()
    .flatten()
    .find({family: 'IPv4', internal: false})
    .value()
    .address;