通过 JS 获取你真实的外网 IP 和内网 IP，就算开代理也没有，想想真是太可怕了，还能不能愉快的装逼了！

Demo

Demo：https://diafygi.github.io/webrtc-ips/

demo

代码

//get the IP addresses associated with an account
function getIPs(callback){
    var ip_dups = {};

    //compatibility for firefox and chrome
    var RTCPeerConnection = window.RTCPeerConnection
        || window.mozRTCPeerConnection
        || window.webkitRTCPeerConnection;

    //bypass naive webrtc blocking
    if (!RTCPeerConnection) {
        var iframe = document.createElement('iframe');
        //invalidate content script
        iframe.sandbox = 'allow-same-origin';
        iframe.style.display = 'none';
        document.body.appendChild(iframe);
        var win = iframe.contentWindow;
        window.RTCPeerConnection = win.RTCPeerConnection;
        window.mozRTCPeerConnection = win.mozRTCPeerConnection;
        window.webkitRTCPeerConnection = win.webkitRTCPeerConnection;
        RTCPeerConnection = window.RTCPeerConnection
            || window.mozRTCPeerConnection
            || window.webkitRTCPeerConnection;
    }

    //minimal requirements for data connection
    var mediaConstraints = {
        optional: [{RtpDataChannels: true}]
    };

    //firefox already has a default stun server in about:config
    //    media.peerconnection.default_iceservers =
    //    [{"url": "stun:stun.services.mozilla.com"}]
    var servers = undefined;

    //add same stun server for chrome
    if(window.webkitRTCPeerConnection)
        servers = {iceServers: [{urls: "stun:stun.services.mozilla.com"}]};

    //construct a new RTCPeerConnection
    var pc = new RTCPeerConnection(servers, mediaConstraints);

    //listen for candidate events
    pc.onicecandidate = function(ice){

        //skip non-candidate events
        if(ice.candidate){

            //match just the IP address
            var ip_regex = /([0-9]{1,3}(\.[0-9]{1,3}){3})/
            var ip_addr = ip_regex.exec(ice.candidate.candidate)[1];

            //remove duplicates
            if(ip_dups[ip_addr] === undefined)
                callback(ip_addr);

            ip_dups[ip_addr] = true;
        }
    };

    //create a bogus data channel
    pc.createDataChannel("");

    //create an offer sdp
    pc.createOffer(function(result){

        //trigger the stun server request
        pc.setLocalDescription(result, function(){}, function(){});

    }, function(){});
}

//Test: Print the IP addresses into the console
getIPs(function(ip){console.log(ip);});

因为Firefox和Chrome支持WebRTC，可以向STUN服务器请求，返回内外网IP，不同于XMLHttpRequest请求，STUN请求开发者工具当中看不到网络请求的。

解决办法

那我们有没有办法继续装逼呢？答案是肯定的。我们可以关闭WebRTC。

Chrome

安装插件 https://chrome.google.com/webstore/detail/webrtc-block/nphkkbaidamjmhfanlpblblcadhfbkdm?hl=en

无法下载的一定是你上网姿势不科学。

Firefox

用 media.peerconnection.enabled 禁用。BTW，方法网上看到了，电脑没装Firefox，所以你们自己摸索吧。

参考资料