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https://dx.doi.org

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
95
GRADE
A
FIX
0
REVIEW
2
PASS
7
INFO
0
Probed from Sao Paulo, Brazil
200 OK
Checks
9
7 PASS 2 REVIEW
B
Crawlability
robots.txt present, no sitemap
REVIEW
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 47 bytes
Info::
No sitemap.xml found
A sitemap helps search engines discover and index your pages more efficiently.
Info::
robots.txt does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

A sitemap helps search engines discover and index your pages more efficiently.

Why this matters

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

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 47 B Sitemaps referenced 0 User-agents * Blocking No — crawling allowed
User-agent: *
Crawl-delay: 1
Request-rate: 1/1

sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

B
TLS Certificate Expiry & Recommendations
58 days until leaf cert expires — 2 issues to address
REVIEW

Certificate validity

58
days left
0d 30d 60d 90d+

Recommended actions

  • Submit your domain to hstspreload.org to be added to the Chrome preload list
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A
DNS Records
3 A records, 18 ms lookup
PASS
3 A records, 18 ms lookup
Info::
Resolves to 3 IPv4 address(es)
Got: 104.26.5.132, 172.67.69.3, 104.26.4.132
Info::
Has 3 IPv6 (AAAA) record(s)
Got: 2606:4700:20::681a:484, 2606:4700:20::681a:584, 2606:4700:20::ac43:4503
Info::
No NS records found
Info::
No MX records — email not configured via DNS
Info::
CAA records not checked
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Info::
No SPF record found in TXT records
SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.
Info::
DNS resolution time: 18 ms
Got: 18 ms
A104.26.5.132, 172.67.69.3, 104.26.4.132
AAAA2606:4700:20::681a:484, 2606:4700:20::681a:584, 2606:4700:20::ac43:4503
CNAME
NS
MX
TXT
CAALookup not available with standard resolver
Resolved in 18 ms

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.

SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.

Why this matters

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)

A+
Redirect Chain
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://dx.doi.org

https://dx.doi.org

21 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://dx.doi.org20021 msHTTP/1.1cloudflare
A+
IPv6 Readiness
IPv6 reachable (1 ms)
PASS
IPv6 reachable (1 ms)
Info::
IPv6 is configured and reachable at 2606:4700:20::681a:484, 2606:4700:20::681a:584, 2606:4700:20::ac43:4503
Got: 1 ms connect
IPv6 Ready
AAAA Records 2606:4700:20::681a:484, 2606:4700:20::681a:584, 2606:4700:20::ac43:4503 Connection Reachable (1 ms)
A+
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
PASS
www/non-www, trailing slash, HTTP→HTTPS
Info::
www/non-www redirect configured correctly (preferred: non-www)
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

301https://www.dx.doi.org/
200https://dx.doi.org/

Preferred variant: non-www

HTTP → HTTPS

301http://dx.doi.org/ https://dx.doi.org/

Consistent

A+
Domain Intelligence
doi.org — via Cloudflare, Inc., 27 years, 7 months old
PASS
doi.org — via Cloudflare, Inc., 27 years, 7 months old
Info::
Domain registered until Jan 19, 2035 (8 years, 10 months remaining)
Info::
DNSSEC is enabled
Info::
Registrar: Cloudflare, Inc.
Warning::
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.
Domain expiry

3111 days

January 19, 2035

SSL certificate

58 days

Issued by Google Trust Services

Domain age

27 years, 7 months

Registered January 19, 1999

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Unknown

2606:4700:20::681a:484

Registrar

Cloudflare, Inc.

Unlocked 2 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar Cloudflare, Inc.
Created January 19, 1999 (27 years, 7 months ago)
Expires January 19, 2035 (8 years, 10 months)
Last Updated July 12, 2025
Name Servers josh.ns.cloudflare.com, zita.ns.cloudflare.com
DNSSEC Enabled
Hosting
IP Address 2606:4700:20::681a:484
Data source: rdap (0.6s)

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

A+
HTTP Probe Timing
Total 20 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
4 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
1 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
7 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
21 ms
Total Time Total request time from DNS lookup through full response.
21 ms

Connection waterfall

DNS Lookup 4 ms TCP Connect 1 ms TLS Handshake 7 ms Server Processing 8 ms Content Transfer 0 ms
A+
CDN & Delivery
Cloudflare (HIT)
PASS
Cloudflare (HIT)
Info::
Site is served via Cloudflare CDN (edge: GRU)
Got: cf-ray: 9efe91035859ef26-GRU
Info::
CDN cache status: HIT
CDN Detected: Cloudflare
Provider Cloudflare Cache Status HIT Evidence cf-ray: 9efe91035859ef26-GRU
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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