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Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
85
GRADE
B
FIX
0
REVIEW
4
PASS
5
INFO
0
Probed from Madrid, Spain
301 Moved Permanently
Checks
9
5 PASS 4 REVIEW
C
IPv6 Readiness
Action
No IPv6 support
REVIEW
No IPv6 support
Info::
No IPv6 (AAAA) records found
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No IPv6 Support
About 40% of internet users have IPv6. Consider adding AAAA records.

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

Why this matters

No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.

Source: Google IPv6 stats

B
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
REVIEW
www/non-www, trailing slash, HTTP→HTTPS
Critical::
Both www and non-www versions serve content
Got: Both variants return 200 Expected: One variant 301-redirects to the other
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

200https://www.stackoverflow.blog/
200https://stackoverflow.blog/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://www.stackoverflow.blog/ https://www.stackoverflow.blog/

Consistent

B
TLS Certificate Expiry & Recommendations
67 days until leaf cert expires — 4 issues to address
REVIEW

Certificate validity

67
days left
0d 30d 60d 90d+

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
B
CDN & Delivery
Netlify
REVIEW
Netlify
Info::
Site is served via Netlify CDN
Got: x-nf-request-id: 01KNMRMMK5C38XKPNXFZDGVV5P
CDN Detected: Netlify
Provider Netlify Evidence x-nf-request-id: 01KNMRMMK5C38XKPNXFZDGVV5P
A
DNS Records
2 A records, 35 ms lookup
PASS
2 A records, 35 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 15.197.167.90, 3.33.186.135
Info::
No IPv6 (AAAA) records
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: 35 ms
Got: 35 ms
A15.197.167.90, 3.33.186.135
AAAA
CNAME
NS
MX
TXT
CAALookup not available with standard resolver
Resolved in 35 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
1 redirect(s), 207 ms total
PASS
1 redirect(s), 207 ms total
Info::
Single redirect
Got: https://www.stackoverflow.blog → https://stackoverflow.blog/ (301)
Info::
WWW normalization redirect

https://www.stackoverflow.blog

79 ms · HTTP/1.1

301

https://stackoverflow.blog/

128 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://www.stackoverflow.blog30179 msHTTP/1.1Netlify
2https://stackoverflow.blog/200128 msHTTP/1.1Netlify

See the visual redirect chain in the HTTP Probe tab →

A+
Crawlability
robots.txt present, sitemap with 3798 URLs
PASS
robots.txt present, sitemap with 3798 URLs
Info::
robots.txt is present
Got: 30 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 3798 entries
Info::
robots.txt does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

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 30 B Sitemaps referenced 0 User-agents GPTBot Blocking No — crawling allowed
User-agent: GPTBot
Disallow: /
A+
Domain Intelligence
stackoverflow.blog — via CSC Corporate Domains Inc., 9 years, 7 months old, hosted on AWS
PASS
stackoverflow.blog — via CSC Corporate Domains Inc., 9 years, 7 months old, hosted on AWS
Info::
Domain registered until Sep 29, 2026 (5 months remaining)
Info::
DNSSEC is not enabled
DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.
Info::
Registrar: CSC Corporate Domains Inc.
Info::
Hosting: AWS
Got: AS16509
Domain expiry

80 days

September 29, 2026

SSL certificate

67 days

Issued by Let's Encrypt

Domain age

9 years, 7 months

Registered September 29, 2016

DNSSEC

Not enabled

Protects against DNS spoofing

Hosting

AWS

ASN AS16509

15.197.167.90

Registrar

CSC Corporate Domains Inc.

Lock status unknown 4 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Renew the domain or enable auto-renewal to prevent accidental expiry
  • Enable DNSSEC to protect visitors from DNS spoofing
Registrar CSC Corporate Domains Inc.
Created September 29, 2016 (9 years, 7 months ago)
Expires September 29, 2026 (5 months)
Last Updated August 23, 2025
Name Servers dns1.p02.nsone.net, dns2.p02.nsone.net, dns3.p02.nsone.net, dns4.p02.nsone.net
DNSSEC Not enabled
Hosting
IP Address 15.197.167.90
ASN AS16509 (AMAZON-02 - Amazon.com, Inc., US)
Provider AWS
Data source: rdap (2.1s)

DNSSEC protects against DNS spoofing attacks. While not required, enabling DNSSEC adds an additional layer of security. Contact your DNS provider to enable it.

Why this matters

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

A
HTTP Probe Timing
Total 515 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
37 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.
64 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
515 ms
Total Time Total request time from DNS lookup through full response.
516 ms

Connection waterfall

DNS Lookup 37 ms TCP Connect 1 ms TLS Handshake 64 ms Server Processing 413 ms Content Transfer 0 ms
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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