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https://knihobot.cz

Infrastructure

· 17 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
90
GRADE
A
FIX
0
REVIEW
9
PASS
8
INFO
0
Probed from New York, United Stated
200 OK
Checks
17
8 PASS 9 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.
B
Reverse DNS
0/3 IPs match cert SAN
REVIEW
0/3 IPs match cert SAN
Info::
PTR for 35.158.36.79 does not match any cert SAN: ec2-35-158-36-79.eu-central-1.compute.amazonaws.com
Common when behind a CDN or shared hosting (PTR points at the provider's hostname). Mismatch can also affect mail deliverability if this IP sends email -- many MTAs reject mail when forward+reverse DNS disagree.
Info::
PTR for 63.186.190.191 does not match any cert SAN: ec2-63-186-190-191.eu-central-1.compute.amazonaws.com
Common when behind a CDN or shared hosting (PTR points at the provider's hostname). Mismatch can also affect mail deliverability if this IP sends email -- many MTAs reject mail when forward+reverse DNS disagree.
Info::
PTR for 63.188.129.201 does not match any cert SAN: ec2-63-188-129-201.eu-central-1.compute.amazonaws.com
Common when behind a CDN or shared hosting (PTR points at the provider's hostname). Mismatch can also affect mail deliverability if this IP sends email -- many MTAs reject mail when forward+reverse DNS disagree.
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
187 days until leaf cert expires — 4 issues to address
REVIEW

Certificate validity

187
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 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
C
CDN & Delivery
Action
Assets on CDN77 (host c77.bookbot.com, 84 assets); document served directly from origin (AWS)
REVIEW
Assets on CDN77 (host c77.bookbot.com, 84 assets); document served directly from origin (AWS)
Warning::
Document not behind existing CDN (CDN77 serves the assets)
The page's subresources are delivered by CDN77 (c77.bookbot.com, 84 assets), but the HTML document itself comes straight from the origin (AWS). Routing the document through the CDN already in use is the cheapest latency win available here -- the provider relationship, the certificate and the config already exist. A short edge TTL with stale-while-revalidate suits HTML that changes often; if the response is genuinely per-user, edge TLS termination alone still removes a full round trip from every visitor's first byte.
Got: delegation 1580667556.rsc.cdn77.org
Info::
Assets on CDN77: c77.bookbot.com (assets: 84)
Got: delegation 1580667556.rsc.cdn77.org
Info::
Assets on CDN77: rezised-images.knhbt.cz (assets: 8)
Got: delegation 1411948082.rsc.cdn77.org
Info::
Assets on CDN77: strapi-c77.bookbot.com (assets: 3)
Got: delegation 1115130612.rsc.cdn77.org
Warning: Assets on a CDN, document is not: CDN77
Document origin AWS

Asset hosts on a CDN

  • c77.bookbot.com — CDN77 · assets: 84
  • rezised-images.knhbt.cz — CDN77 · assets: 8
  • strapi-c77.bookbot.com — CDN77 · assets: 3

Other asset hosts

  • www.googletagmanager.com — assets: 3 · Google
  • l.seznam.cz — assets: 2 · below probe threshold
  • cms.knihobot.cz — assets: 1 · below probe threshold
  • mhubc.knihobot.cz — assets: 1 · below probe threshold

The heavy static files already ride an edge network, but every visitor still waits on the origin for the HTML itself. Routing the document through the same CDN is usually a config change rather than a migration: a short edge TTL with stale-while-revalidate for cacheable HTML, or edge TLS termination alone when the response is per-user.

B
CDN Cache Observability
No CDN cache-status headers in the response
REVIEW
No CDN cache-status headers in the response
Info::
No CDN cache-status headers in the response
Without an X-Cache / CF-Cache-Status / X-Vercel-Cache / Age header, you can't tell from outside whether a request hit the cache or went to origin. Operationally important: enables debugging stale-content reports and verifying cache rules. Most managed CDN platforms emit at least one of these by default; absence often means the platform's diagnostic headers are stripped at an upstream proxy.
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.
B
Health Check Endpoint
No conventional health endpoint found
REVIEW
No conventional health endpoint found
Info::
No conventional health endpoint found
Health endpoints (/health, /healthz, /status, /ping, /api/health) let uptime monitors, load balancers, and orchestration systems (Kubernetes, ECS, Fly.io) verify the service is alive. Marketing sites and small services often skip them legitimately; flagged as Info, not a failure. Probe results: /api/health: 404, /health: 404, /healthz: 404, /ping: 404, /status: 404.
A+
DNS Records
3 A records, 177 ms lookup
PASS
3 A records, 177 ms lookup
Info::
Resolves to 3 IPv4 address(es)
Got: 35.158.36.79, 63.186.190.191, 63.188.129.201
Info::
No IPv6 (AAAA) records
Info::
4 nameserver(s) configured
Got: ns-1224.awsdns-25.org, ns-1706.awsdns-21.co.uk, ns-334.awsdns-41.com, ns-703.awsdns-23.net
Info::
5 mail exchanger(s) configured
Info::
SPF record present in TXT
Info::
DNS resolution time: 177 ms
Got: 177 ms
A35.158.36.79, 63.186.190.191, 63.188.129.201
AAAA
CNAME
NSns-1224.awsdns-25.org, ns-1706.awsdns-21.co.uk, ns-334.awsdns-41.com, ns-703.awsdns-23.net
MX
1 aspmx.l.google.com
5 alt2.aspmx.l.google.com
5 alt1.aspmx.l.google.com
10 alt3.aspmx.l.google.com
10 alt4.aspmx.l.google.com
TXT
MS=ms10914307
facebook-domain-verification=h4g5fa1ox84yafjueot2fk4rnem844
google-site-verification=BrENTn_sxRYDlNHruGdJ-NiZVsUEY9SEUZlyIzj6LNQ
google-site-verification=XPTKqLhnDSxfMVwemejLEPSXTpLLmhBWW_ya07uNDO4
pinterest-site-verification=b4f5518961ee745b3ae991a111a8396e
SPF v=spf1 include:_spf.google.com include:_emailing.heureka.cz include:spf.mailjet....
CAALookup not available with standard resolver
Resolved in 177 ms
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 8ms across 3 resolvers (spread 1ms)
PASS
Mean 8ms across 3 resolvers (spread 1ms)
Info::
Google: 8ms
Got: 8ms via 8.8.8.8:53
Info::
Quad9: 9ms
Got: 9ms via 9.9.9.9:53
Info::
Cloudflare: 9ms
Got: 9ms via 1.1.1.1:53
A+
Redirect Chain
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://knihobot.cz

https://knihobot.cz

479 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://knihobot.cz200479 msHTTP/1.1
A+
Crawlability
robots.txt present, sitemap with 210 URLs
PASS
robots.txt present, sitemap with 210 URLs
Info::
robots.txt is present
Got: 5019 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 210 entries
Info::
Sitemap index with 210 child sitemaps
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 5019 B Sitemaps referenced 1 User-agents SemrushBot, SemrushBot-BA, barkrowler, PetalBot, ImagesiftBot, AwarioBot, ZoominfoBot, SemrushBot-SI, DataForSeoBot, serpstatbot, AliyunSecBot, SemrushBot-SWA, *, meta-externalagent, MJ12bot, BLEXBot Blocking No — crawling allowed
Sitemap: https://knihobot.cz/feeds/sitemaps/sitemap_cz.xml
#Got an SEO tip or an offer for us? Reach out at zdenek.dvorak@knihobot.cz
User-agent: *
#adonis
Disallow: /adonis/*/analytics/
Disallow: /adonis/*/events/
Disallow: /uzivatel/
Allow: /uzivatel/*/knihy-na-prodej
Allow: /uzivatel/*/wishlist
Disallow: /login
Disallow: /account
Disallow: /old_b/
Disallow: /old_m/
Disallow: /old_g/
Disallow: /admin/
Disallow: /manny/
Disallow: /404/
Disallow: /odebratpsa*
Disallow: /kosik
#internal_search
Disallow: /hledani?q=
Disallow: /hledani?ext=
Disallow: /p/q/*
Disallow: /p/q/*/language/1_3
#watchdog
Allow: /watchdog
Disallow: /watchdog?
Disallow: /*?action=user-review
#filters
Disallow: /p/*/author/
Disallow: /p/author/
Disallow: /p/author/*/language/1_3.rating-desc
Disallow: /p/author/*/language/1_3$
Disallow: /p/author/*/language/1_3
Disallow: /p/stitky/*/author/*/language/1_3
Disallow: /p/stitky/*/author/*/language/1_3/page/
Disallow: /p/*/condition/
Disallow: /p/condition/
Disallow: /p/*/language/*_*/condition/
Disallow: /p/*/language/*_*/condition$
Disallow: /p/*/binding/
Disallow: /p/binding/
Disallow: /p/*/language/1_3/binding/1
Disallow: /p/*/year/
Disallow: /p/year/
Disallow: /p/*/language/*/year/
Disallow: /*/instock/
Disallow: /p/instock/
Disallow: /p/stitky/*/language/1_3/instock/
Disallow: /p/*/language/1_3/instock/
Disallow: /p/*/price/
Disallow: /p/price/
Disallow: /p/stitky/*/language/1_3/price/
Disallow: /p/language/*_*
Allow: /p/stitky/*/language/1_3$
Allow: /p/publisher/*
Disallow: /p/publisher/*_
Allow: /p/publisher/*/language/1_3
Disallow: /p/publisher/*_*/
Disallow: /p/publisher/*_*
Disallow: /p/publisher/*_*/language/1_3
Disallow: /p/stitky/*/publisher/
Disallow: /p/kategorie/*/publisher/
#filters exceptions
Allow: /p/year/2025-2025
Disallow: /p/year/2025-2025/*
Disallow: /*/publisher/*/language/
Disallow: /p/publisher/*_*
#filters multiselect
Disallow: /p/stitky/*_
Allow: /p/*/language/1_3$
Disallow: /p/stitky/*_*/language/1_3$
Allow: /p/*/language/1_3.rating-desc
Allow: /p/*/language/1_3
Disallow: /p/*-*_*-*/language/
Disallow: /p/*-*_*-*_*/language/
Disallow: /*/language/*/publisher/
Disallow: /p/*/author/*language/1_3/page
Disallow: /p/*_*
Allow: /p/*/language/1_3/page
Disallow: /p/*/language/1_3_*
Disallow: /p/kategorie/*_
#sorting
Disallow: /p/*.
Allow: /p/*.rating-desc
Disallow: /p/*_*.rating-desc
Disallow: /p/q/*.rating-desc
Disallow: /a/*/*.
Disallow: /p/*/language/1_3.
Disallow: /p/*/language/1_3*.price
#Action page
Disallow: /p/akce/*/stitky/
Disallow: /p/akce/*/language/
Allow: /p/akce/*/language/1_3$
Disallow: /p/akce/*/stitky$
Disallow: /p/akce/*/language$
Disallow: /p/akce/*/publisher$
Disallow: /p/akce/*/publisher/
Disallow: /p/akce/*/kategorie/
Disallow: /p/kategorie/*/.
Disallow: /p/kategorie/*/stitky/
Allow: /p/kategorie/*/language/1_3$
#links
Allow: /p/q/petra%20h%C5%AFlov%C3%A1$
Allow: /p/q/Maso%C5%BErav%C3%A9%20rostliny$
Allow: /p/q/R%C3%A1kosn%C3%ADkov%C3%A1%2C%20Ji%C5%99ina$
Allow: /p/q/%20%D0%A2%D0%B0%D1%82%D1%8C%D1%8F%D0%BD%D0%B0%20%D0%9D%D0%B8%D0%BA%D0%BE%D0%BB%D0%B0%D0%B5%D0%B2%D0%BD%D0%B0%20%D0%9C%D0%B8%D0%BA%D1%83%D1%88%D0%B8%D0%BD%D0%B0/language/13$
Allow: /p/q/Spole%C4%8Densk%C3%BD%20adres%C3%A1%C5%99%20%C4%8Deskoslovensk%C3%BD.%20Ro%C4%8Dn%C3%ADk%201930-1931/language/1_3$
Allow: /p/q/One%20Room%20of%20Happiness%20Spin-off%20-%20The%20Corrupt%20Detective$
Allow: /hledani?q=%22fighting+fantasy%22$
Allow: /p/q/robert%20a%20henlein$
Allow: /p/q/lovecraft$
Allow: /p/q/%C5%A0kvoreck%C3%BD%2C%20Josef/language/3$
Allow: /p/q/objeven%C3%AD%20troje$
Allow: /p/q/Kyncl%2C%20Karel$
Allow: /p/q/Svato%25C5%25A1%2C%2520Michal$
Allow: /p/q/d%C4%9Bsiv%C3%A9%20storky$
Allow: /p/q/Poole%2C%20Gabriella$
Allow: /p/q/%C5%A0kvoreck%C3%BD,%20Josef/language/3
Allow: /p/q/R%C3%A1kosn%C3%ADkov%C3%A1%2C%20Ji%C5%99ina
Allow: /p/q/Svato%25C5%25A1,%2520Michal$
Allow: /p/q/%20%D0%A2%D0%B0%D1%82%D1%8C%D1%8F%D0%BD%D0%B0%20%D0%9D%D0%B8%D0%BA%D0%BE%D0%BB%D0%B0%D0%B5%D0%B2%D0%BD%D0%B0%20%D0%9C%D0%B8%D0%BA%D1%83%D1%88%D0%B8%D0%BD%D0%B0/language/13
Allow: /p/q/Italo%20Calvino$
Allow: /p/q/Mark%C3%A9ta%20Kavale$
Allow: /p/q/%C4%8Dasotvorba$
Allow: /p/q/bilderberg$
Allow: /p/q/Brian%20Lumley$
Allow: /p/q/Spole%C4%8Densk%C3%BD%20adres%C3%A1%C5%99%20%C4%8Deskoslovensk%C3%BD.%20Ro%C4%8Dn%C3%ADk%201930-1931/language/1_3$
Allow: /p/q/Svato%25C5%25A1,%2520Michal$
Allow: /p/q/objeven%C3%AD%20troje$
Allow: /p/q/Mark%C3%A9ta%20Kavale$
Allow: /p/q/Kyncl,%20Karel$
Allow: /p/q/kontrastn%C3%AD%20leporelo/language/1_3$
Allow: /p/q/hovawart$
Allow: /p/q/Vesel%C3%BD%2C%20Karel$
Allow: /p/q/lovecraft$
#Don't let the door hit you on the way out
User-agent: PetalBot
User-agent: BLEXBot
User-agent: SemrushBot
User-agent: meta-externalagent
User-agent: DataForSeoBot
User-agent: PetalBot
User-agent: MJ12bot
User-agent: ImagesiftBot
User-agent: serpstatbot
User-agent: AwarioBot
User-agent: AliyunSecBot
User-agent: ZoominfoBot
User-agent: SemrushBot-SI
User-agent: SemrushBot-BA
User-agent: SemrushBot-SWA
User-agent: barkrowler
Disallow: /
  
sitemap.xml 200 OK
Type Sitemap Index URLs 210 entries Valid XML Yes
Child Sitemaps:
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 redirects to HTTPS permanently
Got: HTTP 301

www / non-www

301https://www.knihobot.cz/
200https://knihobot.cz/

Preferred variant: non-www

HTTP → HTTPS

301http://knihobot.cz/ https://knihobot.cz:443/

Consistent

A+
Domain Intelligence
knihobot.cz — via REG-WEDOS, 7 years, 10 months old, hosted on AWS
PASS
knihobot.cz — via REG-WEDOS, 7 years, 10 months old, hosted on AWS
Info::
Domain registered until Dec 8, 2031 (5 years, 3 months remaining)
Info::
Registrar: REG-WEDOS
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: AS16509
Domain expiry

1914 days

December 8, 2031

SSL certificate

187 days

Issued by Amazon

Domain age

7 years, 10 months

Registered December 9, 2018

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

AWS

ASN AS16509

63.188.129.201

Registrar

REG-WEDOS

Unlocked 4 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 REG-WEDOS
Created December 9, 2018 (7 years, 10 months ago)
Expires December 8, 2031 (5 years, 3 months)
Last Updated April 19, 2022
Name Servers ns-1224.awsdns-25.org, ns-1706.awsdns-21.co.uk, ns-334.awsdns-41.com, ns-703.awsdns-23.net
Hosting
IP Address 63.188.129.201
ASN AS16509 (AMAZON-02 - Amazon.com, Inc., US)
Provider AWS
Data source: rdap (1.2s)

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

Connection waterfall

DNS Lookup 7 ms TCP Connect 84 ms TLS Handshake 87 ms Server Processing 271 ms Content Transfer 7 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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