How to find out the server IP address (using JavaScript) that the browser is connected to?

user_167573 0
Viewed 144178

Is there any way you can find the IP of the server that the browser is connected to? For e.g. if the browser is accessing http://www.google.com, can we tell in any way what IP it is connected to? This is very useful in cases where Round-robin DNS is implemented. So say, the first request to a.com results in 1.1.1.1 & subsequent request result in 1.1.1.2 & so on.

I couldn't find any way to do it with JavaScript. Is it even possible? If not is there any universal way to find this info out?

javascript
11 Answers

You could do a nslookup on location.hostname!

const oReq = new XMLHttpRequest();
oReq.onload = function () {
  const response = JSON.parse(this.responseText);
  alert(JSON.stringify(response.dns_entries));
}  
oReq.open("get", "https://www.enclout.com/api/v1/dns/show.json?auth_token=rN4oqCyJz9v2RRNnQqkx&url=" + encodeURIComponent(location.hostname), true);
oReq.send();

EDIT: Website doesn't work anymore and gets CORS error!

That is now broken, so you can try: Add this to the HTML: <script src="https://cdn.jsdelivr.net/npm/dohjs@latest/dist/doh.min.js"></script> and then in JS:

const resolver = new doh.DohResolver('https://1.1.1.1/dns-query');
resolver.query(location.hostname, 'A')
  .then(response => {
    response.answers.forEach(ans => console.log(ans.data));
  })
  .catch(err => console.error(err));
user_152332760 

<script type="application/javascript">
  function getIP(json) {
    document.write("My public IP address is: ", json.ip);
  }
</script>
<script type="application/javascript" src="http://ipinfo.io/?format=jsonp&callback=getIP"></script>

user_129378370
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