Infrastructure
· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.DCDN & DeliveryActionNo CDN detectedFIX
Consider using a CDN to improve global delivery speed and reduce origin load.
BURL Variantswww/non-www, trailing slash, HTTP→HTTPSREVIEW
www / non-www
HTTP → HTTPS
HTTP version does not redirect to HTTPS
BTLS Certificate Expiry & Recommendations53 days until leaf cert expires — 3 issues to addressREVIEW
Certificate validity
Recommended actions
- Submit your domain to hstspreload.org to be added to the Chrome preload list
- 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 Records1 A records, 16 ms lookupPASS
| A | 209.51.188.116 |
| AAAA | 2001:470:142:5::116 |
| CNAME | — |
| NS | ns1.gnu.org, ns2.gnu.org, ns4.gnu.org |
| MX | 10 eggs.gnu.org |
| TXT | SPF v=spf1 ip4:209.51.188.0/24 ip4:74.94.156.208/28 ip6:2001:470:142::/48 ip6:2603:3... |
| 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.
ARedirect Chain1 redirect(s), 577 ms totalPASS
https://gnu.org
280 ms · HTTP/1.1
https://www.gnu.org/
297 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://gnu.org | 301 | 280 ms | HTTP/1.1 | Apache |
| 2 | https://www.gnu.org/ | 200 | 297 ms | HTTP/1.1 | Apache |
See the visual redirect chain in the HTTP Probe tab →
A+IPv6 ReadinessIPv6 reachable (80 ms)PASS
A+Crawlabilityrobots.txt present, sitemap with 1 URLsPASS
# robots.txt for http://www.gnu.org/
User-agent: *
Crawl-delay: 4
Disallow: */CVS/
Disallow: */po/
Disallow: */workshop/
Disallow: /cgi-bin/
Disallow: /copyleft/
Disallow: /gnu.css
Disallow: /gnusearch/
Disallow: /norobotsnorhumansshouldevervisithispage/
Disallow: /prep/gnumaint/
Disallow: /prep/wrappers-and-scripts/
Disallow: /private/
Disallow: /rss/
Disallow: /savannah-checkouts/
Disallow: /screenshots/
Disallow: /server/banners/
Disallow: /server/body-include*
Disallow: /server/bottom-notes*
Disallow: /server/footer*
Disallow: /server/fs-gang*
Disallow: /server/generic*
Disallow: /server/gnun/
Disallow: /server/head-include*
Disallow: /server/header*
Disallow: /server/html5-head-include*
Disallow: /server/html5-header*
Disallow: /server/include-file-list*
Disallow: /server/outdated*
Disallow: /server/select-language.html
Disallow: /server/source/
Disallow: /server/staging/
Disallow: /server/top-addendum*
Disallow: /server/trans-map.html
Disallow: /server/whatsnew_translations.xml
Disallow: /software/gnun/linc/
Disallow: /software/gnun/proofread/
Disallow: /software/gnun/reports/
Disallow: /software/gnun/test/
Disallow: /usenet/
Sitemap: http://www.gnu.org/sitemap.xml
# Majestic - SEO
User-agent: MJ12bot
Disallow: /
# DataForSeo - SEO
User-agent: DataForSeoBot
Disallow: /
# webmeup - SEO
User-agent: BLEXBot
Disallow: /
# Ahrefs - SEO
User-agent: AhrefsBot
Disallow: /
# babbar - SEO
User-agent: barkrowler
Disallow: /
# Screamingfrog - SEO
User-agent: Screaming Frog SEO Spider
Disallow: /
# Seozoom - SEO
User-Agent: ZoomBot
Disallow: /
# Brandwatch - SEO
User-agent: magpie-crawler
Disallow: /
# Begin Moz - SEO
# Not to be confused with Mozilla.
User-agent: DotBot
Disallow: /
User-agent: rogerbot
Disallow: /
# End Moz - SEO
# Begin Semrush - SEO
User-agent: SemrushBot
Disallow: /
User-agent: SiteAuditBot
Disallow: /
User-agent: SemrushBot-BA
Disallow: /
User-agent: SemrushBot-SI
Disallow: /
User-agent: SemrushBot-SWA
Disallow: /
User-agent: SplitSignalBot
Disallow: /
User-agent: SemrushBot-OCOB
Disallow: /
# End Semrush - SEO
# cognitiveSEO - SEO
User-agent: JamesBOT
Disallow: /
# oncrawl - SEO
User-agent: Oncrawl
Disallow: /
# BEGIN Awario - Marketing
User-agent: AwarioRssBot
Disallow: /
User-agent: AwarioSmartBot
Disallow: /
User-agent: AwarioBot
Disallow: /
# END Awario - Marketing
# SERPSTAT - SEO
User-agent: serpstatbot
Disallow: /
# website-datenbank.de - Search engine?
User-agent: netEstate NE Crawler
Disallow: /
# Ignores crawl-delay and does not help us.
User-Agent: panscient.com
Disallow: /
# Aggressive Latvian Academic Integrity bot that does not help us.
User-agent: AcademicBotRTU
Disallow: /
# See RT #1298215 about internationalization and localization abuse.
# See RT #1638325 about localization, Savannah, and more.
# See RT #2171216 about redirections and unused files.
A+Domain Intelligencegnu.org — via Gandi SAS, 30 years, 10 months oldPASS
98 days
November 23, 2026
53 days
Issued by Let's Encrypt
30 years, 10 months
Registered November 24, 1995
Not enabled
Protects against DNS spoofing
Unknown
2001:470:142:5::116
Gandi SAS
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