Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Probed from Madrid, Spain

301 Moved Permanently

Checks

2 PASS 6 REVIEW 1 FIX

CDN & Delivery

Action

No CDN detected

FIX

No CDN detected

A CDN can significantly improve load times for users around the world by caching content at edge nodes closer to them.

No CDN detected

Consider using a CDN to improve global delivery speed and reduce origin load.

Redirect Chain

1 redirect(s), 1710 ms total

REVIEW

1 redirect(s), 1710 ms total

Single redirect

Got: https://4.cn → https://www.4.cn/ (301)

WWW normalization redirect

Redirect overhead: 1710 ms total

Got: 1710 ms

https://4.cn

677 ms · HTTP/1.1

301

https://www.4.cn/

1033 ms · HTTP/1.1 FINAL

#	URL	Status	Time	Protocol	Server
1	https://4.cn	301	677 ms	HTTP/1.1	nginx/1.26.1
2	https://www.4.cn/	200	1033 ms	HTTP/1.1	nginx/1.26.1

See the visual redirect chain in the HTTP Probe tab →

IPv6 Readiness

Action

No IPv6 support

REVIEW

No IPv6 support

No IPv6 (AAAA) records found

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

No IPv6 Support

About 40% of internet users have IPv6. Consider adding AAAA records.

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

Why this matters

No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.

Source: Google IPv6 stats

Crawlability

Action

robots.txt present, sitemap with 0 URLs

REVIEW

robots.txt present, sitemap with 0 URLs

robots.txt is present

Got: 10240 bytes

sitemap.xml is present

sitemap.xml contains invalid XML

Search engines may not be able to parse the sitemap. Fix XML validation errors.

sitemap.xml is empty — no URLs found

An empty sitemap provides no value. Add <url> entries for your pages.

robots.txt does not reference a sitemap

Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

Search engines may not be able to parse the sitemap. Fix XML validation errors.

Why this matters

An unparseable sitemap is silently ignored by Google — the URLs it advertises are never queued for crawl.

Learn more ▾

Google's sitemap parser is strict about XML validity. A single unescaped `&` or unclosed tag invalidates the whole file. Run your sitemap through a validator (Search Console's Sitemaps report flags it) and fix the offending entry. Most generators escape correctly; mistakes usually come from manually-written entries.

Source: sitemaps.org / Google Search Central

An empty sitemap provides no value. Add <url> entries for your pages.

Why this matters

An empty sitemap signals 'no content to index' to Google — actively harmful versus having no sitemap at all.

Learn more ▾

Google compares URLs in the sitemap against URLs it has crawled. An empty sitemap on a site with thousands of pages signals abandonment. Either populate it correctly (most CMSes auto-generate) or delete the file and let Google crawl normally.

Source: Google Search Central / sitemaps.org

Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

Why this matters

robots.txt omits Sitemap: directive — crawlers must fetch /sitemap.xml by convention; reliable but missing the explicit hint.

Source: sitemaps.org

robots.txt 200 OK

Size 10240 B Sitemaps referenced 0 User-agents Blocking No — crawling allowed

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"><link rel="alternate" href="https://www.4.cn/?lang=zh" hreflang="x-default" />
<link rel="alternate" href="https://www.4.cn/?lang=zh" hreflang="zh-Hans" />
<link rel="alternate" href="https://www.4.cn/?lang=en" hreflang="en" />
<link rel="alternate" href="https://www.4.cn/?lang=zh_HK" hreflang="zh-Hant" />
<style>
 .garyBody{
      filter: grayscale(100%);
      -webkit-filter: grayscale(100%);
      -moz-filter: grayscale(100%);
      -ms-filter: grayscale(100%);
      -o-filter: grayscale(100%);
      -webkit-filter: grayscale(1);
    }
</style>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>4.CN - Buy, Sell &amp; Park Domain Names</title><meta name="keywords" content="buy domain, sell domain, domain escrow, domain auction, domain brokerage, domain parking, domain appraisal, domain name, domain, domain marketplace, domain escrow service, transfer domain, affiliate program, chinese domain names" /><meta name="description" content="4.CN is the global and professional marketplace for buying and selling domain names. We have over 1.500.000 domains in our marketplace. Currently we are the leading domain auction platform and domain escrow service provider in China now." /><meta http-equiv="content-language" content="en" /><meta name="author" content="4.CN" />
<meta name="copyright" content="4.CN" />
<meta name="robots" content="all, index, follow, noodp" />
<meta name="msnbot" content="noodp" />
<meta name="googlebot" content="noodp" />
<meta name="slurp" content="noydir" />
<!--<meta name="revisit-after" content="5 days" /> -->
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link href="/img/favicon.ico" rel="shortcut icon" />
<link href="/img/favicon.ico" rel="icon" type="image/ico" />
<link href="/img/index.css" media="screen" rel="stylesheet" type="text/css" >
<link href="/js/front/css/jquery.flexslider.css" media="screen" rel="stylesheet" type="text/css" ><link href="/img/style.css" type="text/css" media="all" rel="stylesheet" />
<link href="/js/front/css/jquery.dialog.css" type="text/css" media="all" rel="stylesheet" />
<link href="/img/en/style.css" type="text/css" media="all" rel="stylesheet" />
</head><script type="text/javascript" src="/js/front/jquery.min.js"></script>
<script type="text/javascript" src="/js/front/jquery.dialog.min.js"></script>
<script type="text/javascript" src="/js/front/locale/dialog-en.min.js"></script>
<script type="text/javascript" src="/js/front/jquery.flexslider-min.js"></script>
<script type="text/javascript" src="/js/front/jquery.cxscroll.min.js"></script>
<script type="text/javascript" src="/js/front/jquery.index.min.js"></script>
<script type="text/javascript" src="/js/front/jquery.duomai.min.js"></script>
<script type="text/javascript" src="/js/front/locale/index-en.js"></script>
<script type="text/javascript" src="/js/front/punycode.js"></script>
<script type="text/javascript" src="/js/static/gt.js"></script><script type="text/javascript">
var serverdate = new Date("April 22, 2026 08:19:17");
var client_language_flag = 'en';

function padlength(what) {
    var output = (what.toString().length==1) ? "0" + what : what;
    return output;
}

function displaytime() {
    serverdate.setSeconds(serverdate.getSeconds()+1)
    var timestring = padlength(serverdate.getHours()) + ":" + padlength(serverdate.getMinutes()) + ":" + padlength(serverdate.getSeconds());
    var other = 'CST';
    other += " (UTC";
    other += '+08:00)';

    $('#navtime').html('4.CN Server Time: 2026-04-22&nbsp;' + timestring + '&nbsp;'+ other);
    timestring = undefined;
}

function closeMobileTop(){
    document.cookie="closetop=1"
    document.getElementById("mobile_bottom").style.display="none";
}
function downloadApp(){
     var type = "other";
     var downloadUri = "https://itunes.apple.com/us/app/jin-ming-wang4.cn/id1196677695?mt=8";

     var ifr = document.createElement('iframe');
     if(type == 'ios'){
         //safari可能不识别iframe.
         ifr.src = "midaizi://";
         ifr.style = "width:1px;height:1px;";
     }else{
         //请勿修改该地址后面的apps/index.否则会影响android那边manifest里面pathPrefix配置
         ifr.src = "midaizi://4.cn/apps/index";
     }
     document.body.appendChild(ifr);
     //800ms后无反应就自动下载
     setTimeout(function(){
         document.body.removeChild(ifr);
         window.location.href = downloadUri;
     }, 800)
}


$(function(){

    window.alert = function(text){
        $.dialog.alert(text);
    }
    
    $(".toolbar").height($(window).height());
    $(".toolbar").css("padding-top",($(window).height()-300)/2+"px");

    $(window).resize(function() {
        $(".toolbar").height($(window).height());
        $(".toolbar").css("padding-top",($(window).height()-300)/2+"px");
    });
    $(".scrollToTop").click(function(){
        $('html,body').animate({scrollTop:0},500);
    });


    $('.sub-nav-ul a').each(function(){
        //出现在当前链接中 朝前匹配  如果是页面锚点 拒绝选中
        if(window.location.href.indexOf(this.href) !== -1 && this.href.indexOf('#') == -1){
            this.className = 'on'
        }
    });
    $('#keyword').focus(function(){
        if($.trim($(this).val()) == 'Please enter keyword or domain') {
            $(this).val('');
        }
    }).blur(function(){
        if($.trim($(this).val()) == '') {
            $(this).val('Please enter keyword or domain');
        }
    });

    $('#handleSearch').submit(function() {
        if($.trim($('#keyword').val()) == 'Please enter keyword or domain') {
            $('#keyword').val('Please enter keyword or domain');
            return false;
        }
    });

    $('tr[id^="r_"]').hover(function(){
        $(this).toggleClass('cur');
    });
    //$('tr[id^="r_"]:odd').addClass("odd");

    /*
    $('tr[id^="r_"]').click(function(event) {
        if (event.target.type !== 'checkbox') {
            $(':checkbox', this).trigger('click');
        }
    });
    */

    $('li[id^="r_"]').each(function(){
        $(this).mouseover(function(){
            $(this).addClass('cur');
        }).mouseout(function(){
            $(this).removeClass('cur');
        });
    });

    //$("ul.actions :first-child").addClass("first");
    //$("ul.actions :last-child").addClass("last");
    setInterval("displaytime()", 1000);
});
</script>


<body >
    <div id="top" style="height: 28px; line-height: 28px; background: #eee;">
  <div class="wrapper" style="width: 980px; margin: 0 auto; color: #999">
   <div class="fl">
            Welcome to 4.CN                        <a href="/member/signin" class="orange" title="Sign In">Sign In</a>
    <a href="/member/signup" class="orange" title="Create an account">Create an account</a>
                    </div>
   <div class="fr topmenu">
    <a href="http://top.4.cn/" class="orange" target="_blank">Top Domains</a>
    <span class="point"> | </span>
    <a href="http://whois.4.cn" class="f333" target="_blank">Whois</a>
    <span class="point"> | </span>
                        <a href="/company/prices">Fee Policies</a>
    <span class="point"> | </span>
    <a href="/help">Help Center</a>
    <span class="point"> | </span>
    <a href="/company/contactus">Contact Us</a>
    <span class="point"> | </span>
    <span class="nav-tool">
                            <a href="http://www.facebook.com/4dotcn" title="Like us on Facebook" target="_blank">
      <img src="/img/flag/facebook.gif" />
     </a>
     <a href="http://www.twitter.com/4dotcn" title="Follow us on Twitter" target="_blank">
      <img src="/img/flag/twitter.gif" />
     </a>
                        </span>
   </div>
  </div>
 </div>
 <div id="header" class="clearfix">
  <div class="logo">
   <h1 title="4.cn" onclick="window.location.href='/'"></h1>
   <a href="/company/contactus" class="phone" target="_blank" title="Contact Us"></a>
  </div>
  <div class="useful">
   <div class="action-search">
    <div class="search-wrap clearfix">
     <form action="/search/result" method="post" id="handleSearch">
      <input name="buynow" value="1" type="hidden">
      <input name="selling" value="1" type="hidden">
      <input name="stock" value="1" type="hidden">
      <input name="hotsale" value="1" type="hidden">
      <input name="auction" value="1" type="hidden">
      <div class="search-text-container">
       <label for="keyword"></label>
       <input id="keyword" value="Please enter keyword or domain" name="keyword" type="text">
      </div>
      <div class="search-btn-container">
       <button type="submit" name="search" value="1">
        <strong class="blue">Search</strong>
       </button>
      </div>
     </form>
    </div>
   </div>
   <div style="margin-top: 5px; padding-left: 10px; width: 500px; overflow: hidden; height: 15px;">
            Hot search:             <a href="/search/result/tags/81/search/1/tlds/0">Disyllable Pinyin.com</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/150/search/1/tlds/0">Repeated Disyllable Pinyin.com</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/74/search/1/">2Letters</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/75/search/1/tlds/0">3Letters.com</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/71/search/1">3Numbers</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/72/search/1/tlds/0">4Numbers.com</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/79/search/1">Monosyllable Pinyin</a>
    &nbsp;&nbsp;&nbsp;
    <a href="/search/result/tags/77/search/1">2Charaters</a>
    &nbsp;&nbsp;&nbsp;
   </div>
  </div>
 </div>
<!--导航栏-->
 <style>
/* app scan qrcode*/
#nav .nav_mobile_container {
 display: block;
 text-align: center;
 position: relative;
}

#nav .nav_mobile_container .qrcode {
 display: none;
 position: absolute;
 width: 100px;
 height: 100px;
 top: 36px;
 left: 15px;
 z-index: 9999
}

#nav .nav_mobile_container:hover .qrcode {
 display: block
}
</style>
 <div id="nav">
  <ul class="fl">
                            <

sitemap.xml 200 OK

Type URL Set URLs 0 entries Valid XML No

URL Variants

www/non-www, trailing slash, HTTP→HTTPS

REVIEW

www/non-www, trailing slash, HTTP→HTTPS

Both www and non-www versions serve content

Got: Both variants return 200 Expected: One variant 301-redirects to the other

HTTP correctly 301-redirects to HTTPS

www / non-www

200https://www.4.cn/

200https://4.cn/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://4.cn/ → https://www.4.cn/

Consistent

HTTP Probe Timing

Action

Total 1894 ms — DNS, TCP, TLS, TTFB, content transfer breakdown

REVIEW

DNS Lookup

1.25 s

TCP Connect

162 ms

TLS Handshake

326 ms

Time to First Byte

1.89 s

Total Time

1.89 s

Connection waterfall

DNS Lookup 1.25 s TCP Connect 162 ms TLS Handshake 326 ms Server Processing 162 ms Content Transfer 0 ms

TLS Certificate Expiry & Recommendations

76 days until leaf cert expires — 4 issues to address

REVIEW

Certificate validity

days left

0d 30d 60d 90d+

Recommended actions

Prefer TLS 1.3 — TLS 1.2 is acceptable but TLS 1.3 removes RSA key exchange and improves latency
Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
Enable DNSSEC on your domain for DNS spoofing protection
Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy

A+

DNS Records

1 A records, 40 ms lookup

PASS

1 A records, 40 ms lookup

Resolves to 1 IPv4 address(es)

Got: 69.234.239.50

Single A record — no DNS redundancy

Multiple A records provide failover if one server goes down.

No IPv6 (AAAA) records

2 nameserver(s) configured

Got: vip3.alidns.com, vip4.alidns.com

1 mail exchanger(s) configured

CAA records not checked

CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.

SPF record present in TXT

DNS resolution time: 40 ms

Got: 40 ms

A	69.234.239.50
AAAA	—
CNAME	—
NS	vip3.alidns.com, vip4.alidns.com
MX	10 mail.tutanota.de
TXT	SPF v=spf1 include:spf1.dm.aliyun.com -all SPF v=spf1 include:mailgun.org ~all SPF v=spf1 include:spf.tutanota.de -all t-verify=89ffdcb4e2e1d153eb5e018a03d3a8a9 google-site-verification=pVWTtlccvil-QpeXyjIxnTgjkilaa5ohh4uyueBGEKM
CAA	Lookup not available with standard resolver

Resolved in 40 ms

Multiple A records provide failover if one server goes down.

Why this matters

Single A record means a single point of failure — if that IP goes down, your site is unreachable until DNS TTL expires.

Learn more ▾

Add multiple A records for round-robin failover, or use a managed DNS provider with health-checked failover (Route 53, Cloudflare, NS1). Short TTL (60-300s) lets clients recover faster on outages.

Source: SRE practice / DNS architecture

CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.

Why this matters

Informational: CAA (Certification Authority Authorization) records weren't checked in this scan.

A+

Domain Intelligence

4.cn — via 厦门易名科技股份有限公司, 23 years, 5 months old, hosted on WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN

PASS

4.cn — via 厦门易名科技股份有限公司, 23 years, 5 months old, hosted on WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN

Domain registered until Mar 17, 2034 (8 years remaining)

Registrar: 厦门易名科技股份有限公司

Registrar lock is enabled

Domain cannot be transferred without explicit unlock from the registrar. This protects against unauthorized transfers.

Hosting: WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN

Got: AS135629

Domain expiry

2832 days

March 17, 2034

SSL certificate

76 days

Issued by Let's Encrypt

Domain age

23 years, 5 months

Registered March 17, 2003

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN

ASN AS135629

69.234.239.50

Registrar

厦门易名科技股份有限公司

Locked 2 NS records

Expiry timeline

Today

+1 year

Domain expiry SSL expiry Danger zone (≤30 days)

Registrar 厦门易名科技股份有限公司

Created March 17, 2003 (23 years, 5 months ago)

Expires March 17, 2034 (8 years)

Name Servers vip3.alidns.com, vip4.alidns.com

Hosting

IP Address 69.234.239.50

ASN AS135629 (WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN)

Provider WESTCLOUDDATA Ningxia West Cloud Data Technology Co.Ltd., CN

Data source: whois (2.2s)

Domain cannot be transferred without explicit unlock from the registrar. This protects against unauthorized transfers.

Why this matters

Registrar lock (clientTransferProhibited et al.) prevents unauthorized domain transfers — strongest defense against domain hijacking.

Source: ICANN / domain-security best practice

All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.