W3Schools Tryit Editor

const os = require('os');

// Get network interfaces
const networkInterfaces = os.networkInterfaces();
console.log('Network Interfaces:');
console.log(JSON.stringify(networkInterfaces, null, 2));

// Iterate through network interfaces
Object.keys(networkInterfaces).forEach((interfaceName) => {
  console.log(`\nInterface: ${interfaceName}`);

networkInterfaces[interfaceName].forEach((intf) => {
    console.log(`  Address Family: ${intf.family}`);
    console.log(`  IP Address: ${intf.address}`);
    console.log(`  Netmask: ${intf.netmask}`);
    if (intf.mac) {
      console.log(`  MAC Address: ${intf.mac}`);
    }
    console.log(`  Internal: ${intf.internal ? 'Yes' : 'No'}`);
  });
});

// Function to get primary IPv4 address (non-internal)
function getPrimaryIPv4Address() {
  const interfaces = os.networkInterfaces();
  for (const name of Object.keys(interfaces)) {
    for (const intf of interfaces[name]) {
      // Skip internal and non-IPv4 addresses
      if (!intf.internal && intf.family === 'IPv4') {
        return intf.address;
      }
    }
  }
  return 'No IPv4 address found';
}

console.log(`\nPrimary IPv4 Address: ${getPrimaryIPv4Address()}`);

Network Interfaces:
{
  "lo": [
    {
      "address": "127.0.0.1",
      "netmask": "255.0.0.0",
      "family": "IPv4",
      "mac": "00:00:00:00:00:00",
      "internal": true,
      "cidr": "127.0.0.1/8"
    },
    {
      "address": "::1",
      "netmask": "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
      "family": "IPv6",
      "mac": "00:00:00:00:00:00",
      "internal": true,
      "cidr": "::1/128",
      "scopeid": 0
    }
  ],
  "eth0": [
    {
      "address": "192.168.1.1",
      "netmask": "255.255.255.0",
      "family": "IPv4",
      "mac": "aa:bb:cc:dd:ee:ff",
      "internal": false,
      "cidr": "192.168.1.1/24"
    },
    {
      "address": "aa00::bb11:cc22:dd33:ee44%eth0",
      "netmask": "ffff:ffff:ffff:ffff::",
      "family": "IPv6",
      "mac": "aa:bb:cc:dd:ee:ff",
      "internal": false,
      "cidr": "aa00::bb11:cc22:dd33:ee44%eth0/64",
      "scopeid": 1
    }
  ]
}

Interface: lo
  Address Family: IPv4
  IP Address: 127.0.0.1
  Netmask: 255.0.0.0
  MAC Address: 00:00:00:00:00:00
  Internal: Yes
  Address Family: IPv6
  IP Address: ::1
  Netmask: ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
  MAC Address: 00:00:00:00:00:00
  Internal: Yes

Interface: eth0
  Address Family: IPv4
  IP Address: 192.168.1.1
  Netmask: 255.255.255.0
  MAC Address: aa:bb:cc:dd:ee:ff
  Internal: No
  Address Family: IPv6
  IP Address: aa00::bb11:cc22:dd33:ee44%eth0
  Netmask: ffff:ffff:ffff:ffff::
  MAC Address: aa:bb:cc:dd:ee:ff
  Internal: No

Primary IPv4 Address: 192.168.1.1