Infrastructure
· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.BDNS Records1 A records, 29 ms lookupREVIEW
| A | 23.185.0.4 |
| AAAA | 2620:12a:8001::4, 2620:12a:8000::4 |
| CNAME | live-docker.pantheonsite.io |
| NS | — |
| MX | — |
| TXT | — |
| 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 CNAME at the zone apex can break MX and NS records. Use ALIAS/ANAME or A records instead.
CNAME at the apex (example.com) breaks every other apex record (MX, TXT, NS) — DNS-protocol violation per RFC 1034.
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RFC 1034 forbids CNAME alongside other records at the same name. Some DNS providers offer ALIAS / ANAME / flattened-CNAME records that work around this — use those instead. Otherwise apex-level CNAME breaks email (no MX), domain ownership verification (no TXT), and more.
Source: RFC 1034
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.
SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.
Without SPF, receiving servers can't validate sending IPs — your domain is easier to spoof in phishing.
Learn more ▾ ▴
SPF complements DMARC. Both should be published. SPF records list authorized sending IPs (e.g., `v=spf1 include:_spf.google.com ~all` for Google Workspace). After publishing, verify in Google Postmaster Tools or mxtoolbox.
Source: RFC 7208 (SPF)
BTLS Certificate Expiry & Recommendations83 days until leaf cert expires — 4 issues to addressREVIEW
Certificate validity
Recommended actions
- Add includeSubDomains to the HSTS directive
- 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
A+Redirect ChainNo redirects — direct accessPASS
https://www.docker.com
15 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://www.docker.com | 200 | 15 ms | HTTP/1.1 | nginx |
A+IPv6 ReadinessIPv6 reachable (1 ms)PASS
A+Crawlabilityrobots.txt present, sitemap with 15 URLsPASS
User-agent: *
Allow: /wp-admin/admin-ajax.php
Disallow: /wp-admin/
Disallow: /pricing/contact-sales/bss-cc-thankyou/
Disallow: /pricing/contact-sales/bss-thankyou/
Disallow: /company/contact-thank-you/
Disallow: /thank-you-subscribing-docker-weekly/
Disallow: /pricing/contact-sales2/
Disallow: /cdn-cgi/
Disallow: /static/
Disallow: /c/
Disallow: /p/
Disallow: /products/telepresence-for-docker/thank-you/
Disallow: /style-guide/
Disallow: /search/
Allow: /ja-jp/wp-admin/admin-ajax.php
Disallow: /ja-jp/wp-admin/
Disallow: /ja-jp/pricing/contact-sales/bss-cc-thankyou/
Disallow: /ja-jp/pricing/contact-sales/bss-thankyou/
Disallow: /ja-jp/company/contact-thank-you/
Disallow: /ja-jp/thank-you-subscribing-docker-weekly/
Disallow: /ja-jp/pricing/contact-sales2/
Disallow: /ja-jp/cdn-cgi/
Disallow: /ja-jp/static/
Disallow: /ja-jp/c/
Disallow: /ja-jp/products/telepresence-for-docker/thank-you/
Disallow: /ja-jp/style-guide/
Sitemap: https://www.docker.com/sitemap_index.xml
Sitemap: https://www.docker.com/ja-jp/sitemap_index.xml
- https://www.docker.com/post-sitemap1.xml
- https://www.docker.com/post-sitemap2.xml
- https://www.docker.com/post-sitemap3.xml
- https://www.docker.com/post-sitemap4.xml
- https://www.docker.com/post-sitemap5.xml
- https://www.docker.com/page-sitemap.xml
- https://www.docker.com/contributor-sitem...
- https://www.docker.com/contributor-sitem...
- https://www.docker.com/contributor-sitem...
- https://www.docker.com/news-sitemap.xml
- https://www.docker.com/customer-sitemap....
- https://www.docker.com/event-sitemap.xml
- https://www.docker.com/newsletter-sitema...
- https://www.docker.com/video-sitemap.xml
- https://www.docker.com/local-sitemap.xml
A+URL Variantswww/non-www, trailing slash, HTTP→HTTPSPASS
www / non-www
Preferred variant: www
HTTP → HTTPS
Consistent
A+Domain Intelligencedocker.com — via Gandi SAS, 31 years, 7 months oldPASS
224 days
January 26, 2027
83 days
Issued by Let's Encrypt
31 years, 7 months
Registered January 25, 1995
Not enabled
Protects against DNS spoofing
Unknown
2620:12a:8001::4
Gandi SAS
Expiry timeline
Recommended actions
- Enable DNSSEC to protect visitors from DNS spoofing
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