Skip to content
https://linux.com

Infrastructure

· 17 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
89
GRADE
B
FIX
0
REVIEW
6
PASS
11
INFO
0
Probed from Madrid, Spain
301 Moved Permanently
Checks
17
11 PASS 6 REVIEW
B
DNSSEC
Unsigned (DNSSEC not deployed)
REVIEW
Unsigned (DNSSEC not deployed)
Info::
DNSSEC is not deployed
The zone is not DNSSEC-signed. Users on validating resolvers (Cloudflare 1.1.1.1, Quad9 9.9.9.9, growing default in mobile resolvers) get no protection against DNS spoofing for this domain. Most registrars now offer DNSSEC at a single click; consider enabling it for sites where authenticity matters (banking, healthcare, government).
B
CAA Records
No CAA records (any CA may issue certificates)
REVIEW
No CAA records (any CA may issue certificates)
Info::
No CAA records published
Without CAA records, any publicly-trusted CA can issue certificates for this domain. Adding a CAA record (`yourdomain. IN CAA 0 issue "letsencrypt.org"`) restricts issuance to CAs you authorize. Required by CAB Forum baseline since 2017; the default of 'any CA' is widely supported but is the broader attack surface for issuance fraud.
C
Reverse DNS
Action
0/3 IPs match cert SAN
REVIEW
0/3 IPs match cert SAN
Info::
PTR lookup failed for 23.185.0.3: lookup 23.185.0.3: no such host
No reverse DNS record set for this IP. Common on bare cloud-VM IPs without provider-side PTR; not a security issue.
Info::
PTR lookup failed for 2620:12a:8000::3: lookup 2620:12a:8000::3: no such host
No reverse DNS record set for this IP. Common on bare cloud-VM IPs without provider-side PTR; not a security issue.
Info::
PTR lookup failed for 2620:12a:8001::3: lookup 2620:12a:8001::3: no such host
No reverse DNS record set for this IP. Common on bare cloud-VM IPs without provider-side PTR; not a security issue.
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 redirects to HTTPS permanently
Got: HTTP 301

www / non-www

200https://www.linux.com/
200https://linux.com/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://linux.com/ → https://linux.com/

Consistent

B
TLS Certificate Expiry & Recommendations
37 days until leaf cert expires — 5 issues to address
REVIEW

Certificate validity

37
days left
0d 30d 60d 90d+

Recommended actions

  • Extend HSTS max-age to at least 31536000 (1 year) to meet the preload list criteria
  • 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
Operational Status Page
No status page link detected
REVIEW
No status page link detected
Info::
No operational status page link detected
Status pages communicate planned maintenance and incidents to users -- a hallmark of operationally-mature services. Most SaaS teams publish one via Atlassian Statuspage, Instatus, BetterUptime, or a self-hosted Cachet. Smaller sites legitimately don't need one; flagged as Info, not a failure.
A+
DNS Records
1 A records, 50 ms lookup
PASS
1 A records, 50 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 23.185.0.3
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
Has 2 IPv6 (AAAA) record(s)
Got: 2620:12a:8000::3, 2620:12a:8001::3
Info::
4 nameserver(s) configured
Got: ns3.dnsimple-edge.io, ns1.dnsimple-edge.com, ns4.dnsimple-edge.org, ns2.dnsimple-edge.net
Info::
2 mail exchanger(s) configured
Info::
SPF record present in TXT
Info::
DNS resolution time: 50 ms
Got: 50 ms
A23.185.0.3
AAAA2620:12a:8000::3, 2620:12a:8001::3
CNAME—
NSns3.dnsimple-edge.io, ns1.dnsimple-edge.com, ns4.dnsimple-edge.org, ns2.dnsimple-edge.net
MX
10 mx1.forwardemail.net
10 mx2.forwardemail.net
TXT
SPF v=spf1 ip4:198.145.29.98 include:_spf.google.com include:amazonses.com include:m...
globalsign-domain-verification=GAw3QxpoQCUd6MEBcIrvwmn1548c2kZ_M8jDU57Ho3
google-site-verification=SDW6U9788xC80xinO4aDxrgD4bkaCjLozXPv4R7oMbk
google-site-verification=AqV3SU_MRUY0GYnNYAKi_6pa0S1WU7hfq5SapcMUycI
8112310.spf10.hubspotemail.net
google-site-verification=oGlHyAcoij5H-f9oD_WyPZLySBNASgAGQxkmbrKFblo
forward-email-site-verification=JV5pfF4sKV
CAALookup not available with standard resolver
Resolved in 50 ms

Multiple A records provide failover if one server goes down.

Why this matters

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 Takeover
No subdomain takeover risk detected
PASS
No subdomain takeover risk detected
Info::
No CNAME record present
A+
Multi-Resolver DNS Speed
Mean 32ms across 3 resolvers (spread 34ms)
PASS
Mean 32ms across 3 resolvers (spread 34ms)
Info::
Cloudflare: 19ms
Got: 19ms via 1.1.1.1:53
Info::
Google: 25ms
Got: 25ms via 8.8.8.8:53
Info::
Quad9: 53ms
Got: 53ms via 9.9.9.9:53
A
Redirect Chain
1 redirect(s), 22 ms total
PASS
1 redirect(s), 22 ms total
Info::
Single redirect
Got: https://linux.com → https://www.linux.com/ (301)
Info::
WWW normalization redirect

https://linux.com

12 ms · HTTP/1.1

301

https://www.linux.com/

10 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://linux.com30112 msHTTP/1.1nginx
2https://www.linux.com/20010 msHTTP/1.1nginx

See the visual redirect chain in the HTTP Probe tab →

A+
IPv6 Readiness
IPv6 reachable (0 ms)
PASS
IPv6 reachable (0 ms)
Info::
IPv6 is configured and reachable at 2620:12a:8000::3, 2620:12a:8001::3
Got: 0 ms connect
IPv6 Ready
AAAA Records 2620:12a:8000::3, 2620:12a:8001::3 Connection Reachable (0 ms)
A+
Crawlability
robots.txt present, sitemap with 116 URLs
PASS
robots.txt present, sitemap with 116 URLs
Info::
robots.txt is present
Got: 114 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 116 entries
Info::
Sitemap index with 116 child sitemaps
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 114 B Sitemaps referenced 1 User-agents * Blocking No — crawling allowed
User-agent: *
Disallow: /wp-admin/
Allow: /wp-admin/admin-ajax.php

Sitemap: https://www.linux.com/wp-sitemap.xml
sitemap.xml 200 OK
Type Sitemap Index URLs 116 entries Valid XML Yes
Child Sitemaps:
A+
Domain Intelligence
linux.com — via 1API GmbH, 32 years, 8 months old
PASS
linux.com — via 1API GmbH, 32 years, 8 months old
Info::
Domain registered until Jun 1, 2027 (9 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: 1API GmbH
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

279 days

June 1, 2027

SSL certificate

37 days

Issued by Let's Encrypt

Domain age

32 years, 8 months

Registered June 2, 1994

DNSSEC

Not enabled

Protects against DNS spoofing

Hosting

Unknown

2620:12a:8001::3

Registrar

1API GmbH

Unlocked 4 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable DNSSEC to protect visitors from DNS spoofing
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar 1API GmbH
Created June 2, 1994 (32 years, 8 months ago)
Expires June 1, 2027 (9 months)
Last Updated May 27, 2026
Name Servers ns1.dnsimple-edge.com, ns2.dnsimple-edge.net, ns3.dnsimple-edge.io, ns4.dnsimple-edge.org
DNSSEC Not enabled
Hosting
IP Address 2620:12a:8001::3
Data source: rdap (0.2s)

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

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

Connection waterfall

DNS Lookup 51 ms TCP Connect 0 ms TLS Handshake 4 ms Server Processing 11 ms Content Transfer 0 ms
A+
CDN & Delivery
Fastly (HIT, HIT, MISS, MISS)
PASS
Fastly (HIT, HIT, MISS, MISS)
Info::
Site is served via Fastly CDN
Got: x-served-by: cache-chi-klot8100057-CHI, cache-toj-leto2350071-TOJ, cache-toj-leto2350036-TOJ, cache-toj-leto2350036-TOJ
Info::
CDN cache status: HIT, HIT, MISS, MISS
CDN Detected: Fastly
Provider Fastly Cache Status HIT, HIT, MISS, MISS Evidence x-served-by: cache-chi-klot8100057-CHI, cache-toj-leto2350071-TOJ, cache-toj-leto2350036-TOJ, cache-toj-leto2350036-TOJ
A+
CDN Cache Observability
Cache state: HIT
PASS
Cache state: HIT
Info::
CDN cache state observable via 4 header(s)
Got: age=7396, x-cache=HIT, HIT, MISS, MISS, x-cache-hits=18, 0, 0, 0, x-served-by=cache-chi-klot8100057-CHI, cache-toj-leto2350071-TOJ, cache-...
A+
Health Check Endpoint
Health endpoint at https://linux.com/api/health (HTTP 200)
PASS
Health endpoint at https://linux.com/api/health (HTTP 200)
Info::
Public health endpoint at https://linux.com/api/health
Got: https://linux.com/api/health
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

Send Feedback