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

200 OK

Checks

3 PASS 3 REVIEW 3 FIX

URL Variants

Action

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

FIX

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 version does not redirect to HTTPS

Got: HTTP 200 Expected: 301 redirect to HTTPS

www / non-www

200https://www.51job.com/

200https://51job.com/

Inconsistent — duplicate content risk

HTTP → HTTPS

200http://51job.com/

HTTP version does not redirect to HTTPS

HTTP Probe Timing

Action

Total 2404 ms — DNS, TCP, TLS, TTFB, content transfer breakdown

FIX

DNS Lookup

322 ms

TCP Connect

214 ms

TLS Handshake

1.41 s

Time to First Byte

2.19 s

Total Time

2.40 s

Connection waterfall

DNS Lookup 322 ms TCP Connect 214 ms TLS Handshake 1.41 s Server Processing 246 ms Content Transfer 215 ms

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.

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>
<html>
<head>
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<meta http-equiv="Content-Type" content="text/html; charset=gbk">
<link rel="icon" href="https://img04.51jobcdn.com/im/mkt/pc/favicon/favicon_51.ico?20221122" type="image/x-icon"/>
<link rel="apple-touch-icon-precomposed" href="https://img04.51jobcdn.com/im/m/logo_h5@3x.jpg">
<title>招聘网_人才网_找工作_求职_上前程无忧 | 51job 找不到该页</title>
<meta name="description" content="前程无忧为企业提供人才招聘、猎头、培训、测评和人事外包在内的全方位的人力资源服务，帮助个人求职者与企业搭建人才招募和人才培养渠道">
<meta name="keywords" content="人才，招聘，简历，工作，面试，薪酬，跳槽，猎头，培训，测评，人事">
<meta name="robots" content="all">
<meta http-equiv="Expires" content="0">
<meta http-equiv="Cache-Control" content="no-cache">
<meta http-equiv="Pragma" content="no-cache">
<link href="//js.51jobcdn.com/in/css/style.css?20230105" rel="stylesheet" type="text/css" />
<link href="//js.51jobcdn.com/in/css/career.css?20230105" rel="stylesheet" type="text/css" />
<link href="//js.51jobcdn.com/in/css/logo.css?20230105" rel="stylesheet" type="text/css" />
<link href="//js.51jobcdn.com/in/css/2017/public/base.css?20230105" rel="stylesheet" type="text/css" />
<link href="//js.51jobcdn.com/in/css/2017/public/panel-pop.css?20230105" rel="stylesheet" type="text/css" />
<link href="//js.51jobcdn.com/in/css/2017/public/form.css?20230105" rel="stylesheet" type="text/css" />
<script language="javascript">
    var _tkd = _tkd || []; //点击量统计用
    var lang = [];
    var supporthttps = 1; //浏览器是否支持https
    var currenthttps = (window.location.protocol === 'https:') ? '1' : '0'; //当前是否为https
    var systemtime = 1748254761674;
    var d_system_client_time = systemtime - new Date().getTime();
    var trackConfig = {
        'version': '',
        'guid': '69d9801bb4404e770fdfd3be6fe4af35',
        'ip': '116.246.3.99',
        'accountid': '',
        'refpage': '',
        'refdomain': '',
        'domain': 'www.51job.com',
        'pageName': 'missing.php',
        'partner': '',
        'islanding': '0',
        'fromdomain': '51job_web',
        'to': '',
        'createDate': '',
        'identityType': '',
        'sensor_url':'//scdata.51job.com/sa?project=production'
    };
    if (window.localStorage instanceof Object)
    {
            }
    window.cfg = {
        lang:'c',
        domain : {
            my : 'http://my.51job.com',
            login : 'https://login.51job.com',
            search : 'https://search.51job.com',
            www : '//www.51job.com',
            jobs : 'https://jobs.51job.com',
            jianli : 'https://jianli.51job.com',
            company : '//company.51job.com',
            i : '//i.51job.com',
            jc : 'https://jc.51job.com',
            map : 'https://map.51job.com',
            m : 'https://m.51job.com',
            cdn : '//js.51jobcdn.com',
            help : 'https://help.51job.com',
            img : '//img02.51jobcdn.com',
            dj : '//it.51job.com',
            mdj : '//mit.51job.com',
            mq : '//mq.51job.com',
            mmq : '//mmq.51job.com',
            kbc : 'https://blanchard.51job.com',
            mtr : 'https://medu.51job.com',
            tr : 'https://edu.51job.com',
            train : '//tr.51job.com',
            shixi : '//shixi.51job.com',
			mwenku : 'https://mwenku.51job.com',
			mqiuzhixin : 'http://m.qiuzhixin.51job.com',
        }
    };

</script>
<script type="text/javascript" src="//js.51jobcdn.com/in/js/2016/pointtrack.js?20211019"></script>
<script>
    var _hmt = _hmt || [];
    (function() {
        var hm = document.createElement("script");
        hm.src = "https://hm.baidu.com/hm.js?1370a11171bd6f2d9b1fe98951541941";//百度统计代码
        var s = document.getElementsByTagName("script")[0];
        s.parentNode.insertBefore(hm, s);
    })();
</script>

<script language="javascript" src="//js.51jobcdn.com/in/js/2016/jquery.js?20230105"></script>
<script language="javascript" src="//js.51jobcdn.com/in/js/sensorsdata/sensorsdata.min.js?20230105"></script>
<script language="javascript" src="//js.51jobcdn.com/in/js/sensorsdata/sensors_gbk_seo.js?20230105"></script>
<script language="javascript" src="//js.51jobcdn.com/in/js/sensorsdata/sensorsini.js?20230105"></script>
</head>
<body>
<div class="header">
    <!-- bar start -->
    <div class="bar">
        <div class="in">
            <div class="language">
                <ul id="languagelist">
                                            <li class="tle"><span class="list">简</span></li>
                        <li class="last">
                            <a href="//www.51job.com/default-e.php" rel="external nofollow">EN</a></li>
                                    </ul>
            </div>
            <div class="uer">
                                    <p class="op">
                        <a data-sensor-id="sensor_home_rightTopLogin" href="https://login.51job.com/login.php?lang=&url=http%3A%2F%2Fwww.51job.com%2Fin%2Fmissing.php&qrlogin=2" rel="external nofollow">登录</a> /
                        <a data-sensor-id="sensor_home_rightTopRegister"v href="https://login.51job.com/register.php?lang=&url=http%3A%2F%2Fwww.51job.com%2Fin%2Fmissing.php&qrlogin=2" rel="external nofollow">注册</a>
                    </p>
                
            </div>

            <div class="appNew">
                <ul>
                    <li>
                        <em class="e_icon"></em><a href="http://app.51job.com/index.html">APP下载</a>
                    </li>
                    <li>
                        <img width="80" height="80" src="//img05.51jobcdn.com/im/2022/logo/pc_topnav_app.png" alt="app download">
                        <p>
                            <a href="http://app.51job.com/index.html">APP下载</a>
                        </p>
                    </li>
                </ul>
            </div>
            <p class="rlk">
                <a href="//baike.51job.com" target="_blank">职场百科</a>
                <span class="lb">&nbsp;</span>
                <a href="//wenku.51job.com" target="_blank">职场文库</a>
                <span class="lb">&nbsp;</span>
                <a href="https://jobs.51job.com" target="_blank">招聘信息</a>
                <span class="lb">&nbsp;</span>
                <a href="https://ehire.51job.com" target="_blank">我要招聘</a>
                <span class="lb">&nbsp;</span>
            </p>
        </div>
        <input type="hidden" id="welname" name="welname" value="欢迎您">
    </div>
    <!-- top end -->
    <!-- 英文版为body添加class -->
    <script>
            </script>
    <!-- nag start -->
    <div class="pop-city" style="display:none;position: absolute; z-index: 1000;" id="area_channel_layer">
    <div class="tle">
        地区选择        <em class="close" onclick="jvascript:$('#area_channel_layer,#area_channel_layer_backdrop').hide();"></em>
    </div>
    <div class="pcon">
        <div class="ht">
            <label>热门城市</label>
                            <a href="//www.51job.com/beijing/">北京</a>
                <a href="//www.51job.com/shanghai/">上海</a>
                <a href="//www.51job.com/guangzhou/">广州</a>
                <a href="//www.51job.com/shenzhen/">深圳</a>
                <a href="//www.51job.com/wuhan/">武汉</a>
                <a href="//www.51job.com/xian/">西安</a>
                <a href="//www.51job.com/hangzhou/">杭州</a>
                <a href="//www.51job.com/nanjing/">南京</a>
                <a href="//www.51job.com/chengdu/">成都</a>
                <a href="//www.51job.com/chongqing/">重庆</a>
                        </div>
        <div class="cbox">
            <ul  id="area_channel_layer_list">
                <li class="on" onclick="areaChannelChangeTab('abc', this)">A B C</li>
                <li onclick="areaChannelChangeTab('def', this)">D E F</li>
                <li onclick="areaChannelChangeTab('gh', this)">G H</li>
                <li onclick="areaChannelChangeTab('jkl', this)">J K L</li>
                <li onclick="areaChannelChangeTab('mnp', this)">M N P</li>
                <li onclick="areaChannelChangeTab('qrs', this)">Q R S</li>
                <li onclick="areaChannelChangeTab('twx', this)">T W X</li>
                <li onclick="areaChannelChangeTab('yz', this)">Y Z</li>
            </ul>
            <div class="clst"  id="area_channel_layer_all">
                    <div class="e" name="area_channel_div_abc">
        <span><a href="//www.51job.com/anshan/">鞍山</a></span>
        <span><a href="//www.51job.com/anqing/">安庆</a></span>
        <span><a href="//www.51job.com/anyang/">安阳</a></span>
        <span><a href="//www.51job.com/beijing/">北京</a></span>
        <span><a href="//www.51job.com/baotou/">包头</a></span>
        <span><a href="//www.51job.com/baoding/">保定</a></span>
        <span><a href="//www.51job.com/bengbu/">蚌埠</a></span>
        <span><a href="//www.51job.com/baoji/">宝鸡</a></span>
        <span><a href="//www.51job.com/binzhou/">滨州</a></span>
        <span><a href="//www.51job.com/changchun/">长春</a></span>
        <span><a href="//www.51job.com/changsha/">长沙</a></span>
        <span><a href="//www.51job.com/chengdu/">成都</a></span>
        <span><a href="//www.51job.com/chongqing/">重庆</a></span>
        <span><a href="//www.51job.com/changzhou/">常州</a></span>
        <span><a href="//www.51job.com/changde/">常德</a></span>
        <span><a href="//www.51job.com/changshu/">常熟</a></span>
        <span><a href="//www.51job.com/cangzhou/">沧州</a></span>
        <span><a href="//www.51job.com/chaozhou/">潮州</a></span>
        <span><a href="//www.51job.com/chenzhou/">郴州</a></span>
        <span><a href="//www.51job.com/chifeng/">赤峰</a></span>
        <span><a href="//www.51job.com/chuzhou/">滁州</a></span>
        <span><a href="//www.51job.com/changzhi/">长治</a></span>
    </div>
    <div class="

sitemap.xml 200 OK

Type URL Set URLs 0 entries Valid XML No

TLS Certificate Expiry & Recommendations

310 days until leaf cert expires — 4 issues to address

REVIEW

Certificate validity

310

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

DNS Records

1 A records, 301 ms lookup

PASS

1 A records, 301 ms lookup

Resolves to 1 IPv4 address(es)

Got: 114.80.176.40

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: dns.51job.com, ns3.51job.com

2 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 is slow (301 ms)

Slow DNS adds latency to every page load. Consider a faster DNS provider.

Got: 301 ms

A	114.80.176.40
AAAA	—
CNAME	—
NS	dns.51job.com, ns3.51job.com
MX	5 mxbiz1.qq.com 10 mxbiz2.qq.com
TXT	SPF v=spf1 ip4:61.129.48.128/25 ip4:218.98.36.40/29 ip4:222.73.233.0/25 ip4:58.215.1... 17j87jzqhc1vtjr8d1mlq3kdm91kxlwv globalsign-domain-verification=oQILnMe2IToIO9bU8iHqhs1_uWKxl4g4Spos6nJ2S6
CAA	Lookup not available with standard resolver

Resolved in 301 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.

Slow DNS adds latency to every page load. Consider a faster DNS provider.

Why this matters

DNS resolution is slow — anycast DNS providers (Cloudflare, Route 53) typically resolve <50ms globally.

Source: DNS performance benchmarks

A+

Redirect Chain

No redirects — direct access

PASS

No redirects — direct access

Got: https://51job.com

https://51job.com

1809 ms · HTTP/1.1 FINAL

#	URL	Status	Time	Protocol	Server
1	https://51job.com	200	1809 ms	HTTP/1.1	nginx

A+

Domain Intelligence

51job.com — via Alibaba Cloud Computing Ltd. d/b/a HiChina (www.net.cn), 27 years, 1 months old, hosted on CHINANET-SHANGHAI-MAN China Telecom Group, CN

PASS

51job.com — via Alibaba Cloud Computing Ltd. d/b/a HiChina (www.net.cn), 27 years, 1 months old, hosted on CHINANET-SHANGHAI-MAN China Telecom Group, CN

Domain registered until Jul 28, 2030 (4 years, 3 months remaining)

DNSSEC is not enabled

DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.

Registrar: Alibaba Cloud Computing Ltd. d/b/a HiChina (www.net.cn)

Registrar lock is NOT enabled

The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.

Hosting: CHINANET-SHANGHAI-MAN China Telecom Group, CN

Got: AS4811

Domain expiry

1506 days

July 28, 2030

SSL certificate

310 days

Issued by DigiCert, Inc.

Domain age

27 years, 1 months

Registered July 28, 1999

DNSSEC

Not enabled

Protects against DNS spoofing

Hosting

CHINANET-SHANGHAI-MAN China Telecom Group, CN

ASN AS4811

114.80.176.40

Registrar

Alibaba Cloud Computing Ltd. d/b/a HiChina (www.net.cn)

Unlocked 11 NS records

Expiry timeline

Today

+1 year

Domain expiry SSL expiry Danger zone (≤30 days)

Recommended actions

Enable DNSSEC to protect visitors from DNS spoofing
Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers

Registrar Alibaba Cloud Computing Ltd. d/b/a HiChina (www.net.cn)

Created July 28, 1999 (27 years, 1 months ago)

Expires July 28, 2030 (4 years, 3 months)

Last Updated March 16, 2026

Name Servers dns.51job.com, dns.51jobapp.com, ns1.51job.com, ns2.51job.com, ns3.51job.com, ns4.51job.com, ns5.51job.com, ns6.51job.com, ns7.51job.com, ns8.51job.com, ns9.51job.com

DNSSEC Not enabled

Hosting

IP Address 114.80.176.40

ASN AS4811 (CHINANET-SHANGHAI-MAN China Telecom Group, CN)

Provider CHINANET-SHANGHAI-MAN China Telecom Group, CN

Data source: rdap (0.3s)

DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.

Why this matters

Without DNSSEC, an attacker who can poison your DNS can hijack your domain — and SSL certs alone don't stop them.

Learn more ▾

DNSSEC adds cryptographic signatures to DNS records, preventing forged responses from poisoning resolver caches. Without it, an attacker who controls the network path can redirect your domain to a malicious server before any HTTPS handshake happens. Most modern registrars (Cloudflare, Google Domains, Route 53) enable it with one toggle.

Source: ICANN / RFC 4033

The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.

Why this matters

Without registrar lock, an attacker who phishes your registrar credentials can transfer the domain in minutes — total brand hijack.

Learn more ▾

Registrar lock (clientTransferProhibited, clientUpdateProhibited, clientDeleteProhibited) requires extra verification before any transfer/update/delete. Every major registrar offers it free. Combined with 2FA on your registrar account, it's the 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.