Infrastructure
· 17 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.BDNSSECUnsigned (DNSSEC not deployed)REVIEW
CReverse DNSAction0/1 IPs match cert SANREVIEW
CIPv6 ReadinessActionNo IPv6 supportREVIEW
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.
Source: Google IPv6 stats
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.
BTLS Certificate Expiry & Recommendations69 days until leaf cert expires — 3 issues to addressREVIEW
Certificate validity
Recommended actions
- Add the preload directive and submit to hstspreload.org once max-age + includeSubDomains are in place
- 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
BOperational Status PageNo status page link detectedREVIEW
A+DNS Records1 A records, 92 ms lookupPASS
| A | 198.252.206.1 |
| AAAA | — |
| CNAME | — |
| NS | sureena.ns.cloudflare.com, damian.ns.cloudflare.com |
| MX | 1 aspmx.l.google.com 5 alt1.aspmx.l.google.com 5 alt2.aspmx.l.google.com 10 alt3.aspmx.l.google.com 10 alt4.aspmx.l.google.com |
| TXT | docusign=4262531d-29f4-4a62-9f33-ae9f66f5247b google-site-verification=2Bi6SYw5skkRexdtdLPL2gpxeIhLxnYVqITVP9Htl3w atlassian-domain-verification=byLeZgl3MIcfOqwWuMhq8Fhr/1zem/jIaouJegvDZbBKUU5Oqh... google-site-verification=o3EMam8yBGo1yEjyybIiZcOunGHOQKpo8JmOtp9n1BU onetrust-domain-verification=e445562296a64c649ae3d520230b8c4c google-site-verification=rdWtMbplKjbRHGr2dNONfwkqithlUvjr3u6i8QEz_mo MS=ms52592611 google-site-verification=ctogLnZNAdc_CXq8yOhODMLpmugGynjxKecKHDz4oL8 cursor-domain-verification-sb0ayf=Pk6AyptQuTpzpcuSlfYGWloxv anthropic-domain-verification-q70207=cKyy0llXkD10O4rDQpWz8tQ5K make-domain-verification=eec31159-f381-4f38-9d89-e59123dd023e onetrust-domain-verification=0d9d67f856334905a54256085a5768b3 apple-domain-verification=O9jlnJXAQ7sNSZqC ZOOM_verify_AbkNwz5bBl0eurcDKyhhuk adobe-idp-site-verification=25ba5203f3687c9cd6ee3223ee5de1528917828d1da3ebd3bd9a... v=MCPv1; k=ed25519; p=VhBofO8RaYvTvHT7q5tTty+HQeCU8R6h5Y8k/sj20So= ibmid=4e7cbbb3-5f12-40b4-96c7-5b064347b822 SPF v=spf1 ip4:52.38.191.241 include:_spf1.stackoverflow.com ~all profound-domain-verification-5p599x=hWudYd2Du6WOYOod5ko9Rwnp8 openai-domain-verification=dv-GLNufzbWDzAq0fDXHD6jxeCK docker-verification=d65aee54-9091-4ceb-b792-61f5d5804050 |
| 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
A+Subdomain TakeoverNo subdomain takeover risk detectedPASS
A+CAA Recordsissue: comodoca.com, digicert.com, letsencrypt.org, pki.goog, sectigo.com, ssl.com | issuewild: comodoca.com, digicert.com, letsencrypt.org, pki.goog, sectigo.com, ssl.com | iodef configuredPASS
A+Multi-Resolver DNS SpeedMean 12ms across 3 resolvers (spread 19ms)PASS
A+Redirect ChainNo redirects — direct accessPASS
https://stackoverflow.com/users/login
196 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://stackoverflow.com/users/login | 200 | 196 ms | HTTP/1.1 | cloudflare |
A+URL Variantswww/non-www, trailing slash, HTTP→HTTPSPASS
www / non-www
Preferred variant: non-www
Trailing Slash
HTTP → HTTPS
Consistent
A+Domain Intelligencestackoverflow.com — via CSC Corporate Domains, Inc., 22 years, 8 months old, hosted on CloudflarePASS
261 days
February 2, 2027
69 days
Issued by Let's Encrypt
22 years, 8 months
Registered December 26, 2003
Not enabled
Protects against DNS spoofing
Cloudflare
ASN AS13335
198.252.206.1
CSC Corporate Domains, Inc.
Expiry timeline
Recommended actions
- Enable DNSSEC to protect visitors from DNS spoofing
- Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.
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.
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