Infrastructure
· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.DRedirect ChainAction2 redirect(s), 2994 ms totalFIX
https://cas.cn
1077 ms · HTTP/1.1
http://www.cas.cn/
826 ms · HTTP/1.0
https://www.cas.cn/
1091 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://cas.cn | 301 | 1077 ms | HTTP/1.1 | |
| 2 | http://www.cas.cn/ | 302 | 826 ms | HTTP/1.0 | Microsoft-IIS/7.5 |
| 3 | https://www.cas.cn/ | 200 | 1091 ms | HTTP/1.1 |
See the visual redirect chain in the HTTP Probe tab →
Each redirect adds latency. Try to minimize the chain to 1 hop.
Redirect chain — each hop adds latency; combine into one redirect where possible.
Source: Google Search Central / web.dev
Redirect directly from https://cas.cn to https://www.cas.cn/
Redirect chain could be flattened to one hop — server config tweak removes intermediate latency.
Source: web.dev
If permanent, use 301 instead.
302 (Found) is for genuinely temporary redirects — if this redirect is permanent, switch to 301 to preserve SEO equity.
Learn more ▾ ▴
Search engines treat 302 as temporary, keeping the original URL indexed and not transferring full link equity to the destination. Use 301 (Moved Permanently) for permanent redirects (HTTP→HTTPS, www-vs-non-www, URL restructures).
Source: Google Search Central
DURL VariantsActionwww/non-www, trailing slash, HTTP→HTTPSFIX
www / non-www
Inconsistent — duplicate content risk
HTTP → HTTPS
HTTP version does not redirect to HTTPS
DCDN & DeliveryActionNo CDN detectedFIX
Consider using a CDN to improve global delivery speed and reduce origin load.
BCrawlabilityno robots.txt, no sitemapREVIEW
robots.txt is optional but recommended. It tells search engine crawlers which pages to index.
No robots.txt — crawlers fetch /robots.txt and get 404; not breaking but means default crawl behavior with no directives or sitemap reference.
Learn more ▾ ▴
A minimal robots.txt with `User-agent: * / Allow: / / Sitemap: https://example.com/sitemap.xml` covers the basics. Without it, crawlers behave fine but lose the sitemap signal and can't be selectively blocked from crawl-traps.
Source: robotstxt.org
A sitemap helps search engines discover and index your pages more efficiently.
No sitemap.xml — Google relies on crawl-graph discovery alone, slowing indexing of deep or fresh URLs.
Learn more ▾ ▴
A sitemap accelerates Google's discovery of new and updated content. Most CMSes auto-generate one; static-site frameworks need a build-step plugin. Reference it from robots.txt and submit in Search Console to confirm Google can fetch it.
Source: sitemaps.org / Google Search Central
No robots.txt found
This is fine for most sites — a missing robots.txt allows all crawling by default.
No sitemap found
Adding a sitemap helps search engines discover your pages.
BHTTP Probe TimingTotal 1348 ms — DNS, TCP, TLS, TTFB, content transfer breakdownREVIEW
Connection waterfall
BTLS Certificate Expiry & Recommendations240 days until leaf cert expires — 3 issues to addressREVIEW
Certificate validity
Recommended actions
- 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
ADNS Records1 A records, 286 ms lookupPASS
| A | 159.226.242.61 |
| AAAA | 2400:dd01:1017:1000::9fe2:f23d |
| CNAME | — |
| NS | ns3.cstnet.cn, ns4.cstnet.cn |
| MX | 5 mx.cstnet.cn |
| TXT | SPF v=spf1 include:spf.mail.cstnet.cn -all |
| CAA | Lookup not available with standard resolver |
Multiple A records provide failover if one server goes down.
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.
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.
DNS resolution is slow — anycast DNS providers (Cloudflare, Route 53) typically resolve <50ms globally.
Source: DNS performance benchmarks
A+IPv6 ReadinessIPv6 reachable (272 ms)PASS
A+Domain Intelligencecas.cn — via 北京国科云计算技术有限公司（原北京中科三方网络技术有限公司）, 23 years, 5 months oldPASS
3163 days
March 17, 2035
240 days
Issued by China Financial Certification Authority
23 years, 5 months
Registered March 17, 2003
Status unknown
Protects against DNS spoofing
Unknown
2400:dd01:1017:1000::9fe2:f23d
北京国科云计算技术有限公司（原北京中科三方网络技术有限公司）
Expiry timeline
Domain cannot be transferred without explicit unlock from the registrar. This protects against unauthorized transfers.
Registrar lock (clientTransferProhibited et al.) prevents unauthorized domain transfers — strongest defense against domain hijacking.
Source: ICANN / domain-security best practice