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https://rdcu.be

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
78
GRADE
C
FIX
2
REVIEW
2
PASS
5
INFO
0
Probed from Amsterdam, Netherlands
302 Found
Checks
9
5 PASS 2 REVIEW 2 FIX
F
Crawlability
Action
robots.txt present, sitemap with 0 URLs
FIX
robots.txt present, sitemap with 0 URLs
Info::
robots.txt is present
Got: 25 bytes
Critical::
robots.txt blocks all crawlers
Disallow: / for all user-agents prevents search engines from indexing any page. This will remove the site from search results.
Info::
sitemap.xml is present
Warning::
sitemap.xml contains invalid XML
Search engines may not be able to parse the sitemap. Fix XML validation errors.
Warning::
sitemap.xml is empty — no URLs found
An empty sitemap provides no value. Add <url> entries for your pages.
Info::
robots.txt does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

Disallow: / for all user-agents prevents search engines from indexing any page. This will remove the site from search results.

Why this matters

Disallow: / in robots.txt blocks every search crawler — the site becomes invisible in organic search.

Learn more

Common deployment mistake: a staging robots.txt with `User-agent: * / Disallow: /` ships to prod. The site falls out of search results within days. Verify your robots.txt is the production-intended version. If this is intentional (private site), no action needed.

Source: Google Search Central

Search engines may not be able to parse the sitemap. Fix XML validation errors.

Why this matters

An unparseable sitemap is silently ignored by Google — the URLs it advertises are never queued for crawl.

Learn more

Google's sitemap parser is strict about XML validity. A single unescaped `&` or unclosed tag invalidates the whole file. Run your sitemap through a validator (Search Console's Sitemaps report flags it) and fix the offending entry. Most generators escape correctly; mistakes usually come from manually-written entries.

Source: sitemaps.org / Google Search Central

An empty sitemap provides no value. Add <url> entries for your pages.

Why this matters

An empty sitemap signals 'no content to index' to Google — actively harmful versus having no sitemap at all.

Learn more

Google compares URLs in the sitemap against URLs it has crawled. An empty sitemap on a site with thousands of pages signals abandonment. Either populate it correctly (most CMSes auto-generate) or delete the file and let Google crawl normally.

Source: Google Search Central / sitemaps.org

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 25 B Sitemaps referenced 0 User-agents * Blocking Yes — all crawlers blocked
User-agent: *
Disallow: /
sitemap.xml 200 OK
Type URL Set URLs 0 entries Valid XML No
D
CDN & Delivery
Action
No CDN detected
FIX
No CDN detected
Warning::
No CDN detected
A CDN can significantly improve load times for users around the world by caching content at edge nodes closer to them.
No CDN detected

Consider using a CDN to improve global delivery speed and reduce origin load.

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
TLS Certificate Expiry & Recommendations
311 days until leaf cert expires — 3 issues to address
REVIEW

Certificate validity

311
days left
0d 30d 60d 90d+

Recommended actions

  • Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
  • 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 Records
2 A records, 19 ms lookup
PASS
2 A records, 19 ms lookup
Info::
Resolves to 2 IPv4 address(es)
Got: 52.204.59.192, 98.90.173.31
Info::
No IPv6 (AAAA) records
Info::
2 nameserver(s) configured
Got: gina.ns.cloudflare.com, woz.ns.cloudflare.com
Info::
5 mail exchanger(s) configured
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: 19 ms
Got: 19 ms
A52.204.59.192, 98.90.173.31
AAAA
CNAME
NSgina.ns.cloudflare.com, woz.ns.cloudflare.com
MX
10 aspmx.l.google.com
20 alt1.aspmx.l.google.com
30 alt2.aspmx.l.google.com
40 aspmx2.googlemail.com
50 aspmx3.googlemail.com
TXT
CAALookup not available with standard resolver
Resolved in 19 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), 873 ms total
PASS
1 redirect(s), 873 ms total
Info::
Single redirect
Got: https://rdcu.be → https://www.readcube.com (302)
Info::
WWW normalization redirect
Info::
Uses 302 (temporary) redirect
If permanent, use 301 instead.
Got: https://rdcu.be
Info::
Redirect overhead: 873 ms total
Got: 873 ms
Info::
Cross-domain redirect detected

https://rdcu.be

301 ms · HTTP/1.1

302

https://www.readcube.com

573 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://rdcu.be302301 msHTTP/1.1
2https://www.readcube.com200573 msHTTP/1.1cloudflare

See the visual redirect chain in the HTTP Probe tab →

If permanent, use 301 instead.

Why this matters

302 (Found) is for genuinely temporary redirects — if this redirect is permanent, switch to 301 to preserve SEO equity.

Learn more

Search engines treat 302 as temporary, keeping the original URL indexed and not transferring full link equity to the destination. Use 301 (Moved Permanently) for permanent redirects (HTTP→HTTPS, www-vs-non-www, URL restructures).

Source: Google Search Central

A+
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
PASS
www/non-www, trailing slash, HTTP→HTTPS
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

https://www.rdcu.be/
200https://rdcu.be/

HTTP → HTTPS

301http://rdcu.be/ https://rdcu.be:443/

Consistent

A+
Domain Intelligence
rdcu.be — hosted on AWS
PASS
rdcu.be — hosted on AWS
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.
Info::
Hosting: AWS
Got: AS14618
Domain expiry

Unknown

SSL certificate

311 days

Issued by Amazon

Domain age

Unknown

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

AWS

ASN AS14618

98.90.173.31

Registrar

Registrar unknown

Unlocked 2 NS records
Expiry timeline
Today
+1 year
SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar
Name Servers woz.ns.cloudflare.com, gina.ns.cloudflare.com
Registrant Not shown, please visit www.dnsbelgium.be for webbased whois.
Hosting
IP Address 98.90.173.31
ASN AS14618 (AMAZON-AES - Amazon.com, Inc., US)
Provider AWS
Data source: whois (0.7s)

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

Connection waterfall

DNS Lookup 19 ms TCP Connect 93 ms TLS Handshake 95 ms Server Processing 97 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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