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A library for parsing and manipulating IPv6 (and v4) addresses in JavaScript

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javascript-ipv6 Build Status

javascript-ipv6 is a library for manipulating IPv6 addresses in JavaScript.


For node:

var v6 = require('ipv6').v6;

var address = new v6.Address('2001:0:ce49:7601:e866:efff:62c3:fffe');

console.log(address.isValid()); // Prints "true"

var teredo = address.teredo();

console.log(teredo.client4);    // Prints ""

For a browser:

<!DOCTYPE html>
<html lang="en">
  <title>Simple IPv6 test</title>

  <script type="text/javascript" src="//"></script>

  <script type="text/javascript" src="/lib/jsbn.js"></script>
  <script type="text/javascript" src="/lib/jsbn2.js"></script>

  <script type="text/javascript" src="/lib/sprintf.js"></script>

  <script type="text/javascript" src="/ipv6/ipv6.js"></script>

  <script type="text/javascript">
   $(function() {
    var address6 = new v6.Address('a::b');


  The canonical form of <code>a::b</code> is: <code id="output"></code>

Current functionality

  • Parsing of most IPv6 notations
  • Parsing of IPv6 Addresses and Ports from URLs with v6.Address.fromURL(url)
  • Validity checking
  • Decoding of the Teredo information in an address
  • Whether one address is a valid subnet of another
  • What special properties a given address has (multicast prefix, unique local address prefix, etc.)
  • Number of subnets of a certain size in a given address
  • Display methods
    • Hex, binary, and decimal
    • Canonical form
    • Correct form
    • IPv4-compatible (i.e. ::ffff:
  • Works in node.js and the browser
  • Unit tests with node.js and Mocha

Used by

Future functionality

  • Investigate procstreams for the CLI tool
  • Base 64/85 encoding?
  • Reverse lookups? (Whether a domain name has IPv6 glue)


  • Documentation
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