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https://zdf.de

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
90
GRADE
A
FIX
1
REVIEW
2
PASS
6
INFO
0
Probed from Madrid, Spain
301 Moved Permanently
Checks
9
6 PASS 2 REVIEW 1 FIX
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
51 days until leaf cert expires — 4 issues to address
REVIEW

Certificate validity

51
days left
0d 30d 60d 90d+

Recommended actions

  • Prefer TLS 1.3 — TLS 1.2 is acceptable but TLS 1.3 removes RSA key exchange and improves latency
  • 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
1 A records, 38 ms lookup
PASS
1 A records, 38 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 91.197.29.78
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
No IPv6 (AAAA) records
Info::
8 nameserver(s) configured
Got: a1-107.akam.net, a10-64.akam.net, ns01.zdf.de, ns02.zdf.de, a22-67.akam.net, a11-65.akam.net, a14-66.akam.net, a9-66.akam.net
Info::
1 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::
SPF record present in TXT
Info::
DNS resolution time: 38 ms
Got: 38 ms
A91.197.29.78
AAAA—
CNAME—
NSa1-107.akam.net, a10-64.akam.net, ns01.zdf.de, ns02.zdf.de, a22-67.akam.net, a11-65.akam.net, a14-66.akam.net, a9-66.akam.net
MX
15 mail.zdf.de
TXT
ZOOM_verify_Wllf7UjIfNGKc1zFRX8GZ6
google-site-verification=MOFvgZPijgADlwMs-EP7lm6BTgGVRhkbX5t8BdG61nQ
teamviewer-sso-verification=0a46b98a110a4950a4773ead0ebca2bb
0F5FDAA57CC54669BF2D9F3181A7AA1733267250C947FFE163DCC0FD6E518079
miro-verification=7d15c328d1c85b596fe22b6e31bb66591b1752c3
PpqfBkv+dNIvCFJd0nfjMUbz3VsCR9SPUxxjKGuEAtR1e7LaxStzU5+T/RpgnH3OdqEYJQqmcV3DiEDS...
MS=ms99553264
_2ocfue7miy9iq62raa7ci5vj6r3i0xa
apple-domain-verification=lVOPviAnVo9tQfOE
facebook-domain-verification=hb6wb986e73ua5fwxn6t9zfqjq9olp
SPF v=spf1 include:spf1.zdf.de include:spf.protection.outlook.com include:spf.nl2go....
CAALookup not available with standard resolver
Resolved in 38 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

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.

A
Redirect Chain
1 redirect(s), 181 ms total
PASS
1 redirect(s), 181 ms total
Info::
Single redirect
Got: https://zdf.de → https://www.zdf.de/ (301)
Info::
WWW normalization redirect

https://zdf.de

135 ms · HTTP/1.1

301

https://www.zdf.de/

46 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://zdf.de301135 msHTTP/1.1nginx
2https://www.zdf.de/20046 msHTTP/1.1

See the visual redirect chain in the HTTP Probe tab →

A+
Crawlability
robots.txt present, sitemap with 27 URLs
PASS
robots.txt present, sitemap with 27 URLs
Info::
robots.txt is present
Got: 646 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 27 entries
Info::
Sitemap index with 27 child sitemaps
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 646 B Sitemaps referenced 2 User-agents Google-Extended, SemrushBot, Vagabondo, MJ12bot, proximic, scrapybot, sentibot, SEOkicks-Robot, trendkite-akashic-crawler, iCjobs, linkdexbot, scrapy, TkBot, WBSearchBot, grapeshot, MegaIndex, CCBot, GPTBot, ChatGPT-User, magpie-crawler, QuerySeekerSpider Blocking No — crawling allowed
Sitemap: https://www.zdf.de/mediathek-sitemap.xml

Sitemap: https://www.zdf.de/sitemap-zdfunternehmen.xml


User-agent: CCBot

User-agent: Google-Extended

User-agent: GPTBot

User-agent: ChatGPT-User

User-Agent: scrapy

User-Agent: scrapybot

User-Agent: SemrushBot

User-Agent: sentibot

User-Agent: SEOkicks-Robot

User-Agent: TkBot

User-Agent: trendkite-akashic-crawler

User-Agent: Vagabondo

User-Agent: WBSearchBot

User-Agent: grapeshot

User-Agent: iCjobs

User-Agent: linkdexbot

User-Agent: magpie-crawler

User-Agent: MegaIndex

User-Agent: MJ12bot

User-Agent: proximic

User-Agent: QuerySeekerSpider

Disallow: /sport/bundesliga/
sitemap.xml 200 OK
Type Sitemap Index URLs 27 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::
HTTP correctly 301-redirects to HTTPS

www / non-www

403https://www.zdf.de/
200https://zdf.de/

HTTP → HTTPS

301http://zdf.de/ → https://www.zdf.de/

Consistent

A+
Domain Intelligence
zdf.de — hosted on ZDF-AS, DE
PASS
zdf.de — hosted on ZDF-AS, DE
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: ZDF-AS, DE
Got: AS43354
Domain expiry

Unknown

SSL certificate

51 days

Issued by DigiCert Inc

Domain age

Unknown

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

ZDF-AS, DE

ASN AS43354

91.197.29.78

Registrar

Registrar unknown

Unlocked Name servers unknown
Expiry timeline
Today
+1 year
SSL expiry Danger zone (≤30 days)
Recommended actions
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar
Hosting
IP Address 91.197.29.78
ASN AS43354 (ZDF-AS, DE)
Provider ZDF-AS, DE
Data source: whois (0.8s)

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

Connection waterfall

DNS Lookup 38 ms TCP Connect 32 ms TLS Handshake 68 ms Server Processing 33 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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