groupon.de

Checked 21 October 2026, 22:41 UTC · via 8.8.8.8
!Passed with warnings
26 passed 1 warning 0 failed 5 info

Registration

info

.de country-code

Found

TLD
.de (country-code)
ICANN policies apply
no

Checks

  • i
    .de is a country-code TLD (ccTLD)
    Country-code TLD: governed by its local registry under national policy, not by an ICANN contract. Registrar accreditation, dispute resolution and RDAP/WHOIS rules are set by the registry.
    #1
  • ✓ TLD delegated and signed #2
    .de is delegated in the root zone and DNSSEC-signed.
  • i
    Registration data not available
    No registration data via RDAP: the registry of .de offers no RDAP service. Many ccTLD registries don't offer RDAP; check the registry's WHOIS instead.
    #3

Delegation

info

blue.foundationdns.com, blue.foundationdns.net, blue.foundationdns.org

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
blue.foundationdns.com, blue.foundationdns.net, blue.foundationdns.org
NS in the zone
blue.foundationdns.com, blue.foundationdns.net, blue.foundationdns.org
NameserverAddressesNetwork (AS)Glue
blue.foundationdns.com108.162.198.1 162.159.60.1 172.64.40.1 2606:4700:57::6ca2:c601 2a06:98c1:56::ac40:2801 2803:f800:52::a29f:3c01AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US-
blue.foundationdns.net108.162.198.31 162.159.60.31 172.64.40.31 2606:4700:57::6ca2:c61f 2803:f800:52::a29f:3c1f 2a06:98c1:56::ac40:281fAS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US-
blue.foundationdns.org108.162.198.61 162.159.60.61 172.64.40.61 2606:4700:57::6ca2:c63d 2803:f800:52::a29f:3c3d 2a06:98c1:56::ac40:283dAS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US AS13335 CLOUDFLARENET - Cloudflare, Inc., US-

Checks

  • ✓ 3 nameservers #6
    Delegated to blue.foundationdns.com, blue.foundationdns.net, blue.foundationdns.org.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ No glue needed #8
    All nameservers are outside the zone, so no glue records are needed.
  • ✓ All names resolve #9
    Every nameserver name has an address and is not an alias.
  • ✓ Nameservers in different networks #10
    The nameservers are spread over 3 IPv4 /24s and 3 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS13335 (CLOUDFLARENET - Cloudflare, Inc., US): 18 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.
    #11
  • ✓ Nameserver names under 3 TLDs #12
    Nameserver names use the TLDs .com, .net, .org.
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

warn

18 of 18 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
blue.foundationdns.com 108.162.198.1NOERROR, 10 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.com 162.159.60.1NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.com 172.64.40.1NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.com 2606:4700:57::6ca2:c601NOERROR, 10 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.com 2a06:98c1:56::ac40:2801NOERROR, 15 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.com 2803:f800:52::a29f:3c01NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 108.162.198.31NOERROR, 11 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 162.159.60.31NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 172.64.40.31NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 2606:4700:57::6ca2:c61fNOERROR, 11 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 2803:f800:52::a29f:3c1fNOERROR, 15 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.net 2a06:98c1:56::ac40:281fNOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 108.162.198.61NOERROR, 10 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 162.159.60.61NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 172.64.40.61NOERROR, 14 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 2606:4700:57::6ca2:c63dNOERROR, 11 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 2803:f800:52::a29f:3c3dNOERROR, 16 ms, authoritativenoyes / yesrefused2026.10.0
blue.foundationdns.org 2a06:98c1:56::ac40:283dNOERROR, 15 ms, authoritativenoyes / yesrefused2026.10.0

Checks

  • ✓ All respond #14
    All 18 nameserver addresses answered.
  • ✓ All authoritative #15
    Every responding nameserver answers authoritatively for the zone.
  • ✓ No recursion #16
    The nameservers do not answer recursive queries for other domains.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: blue.foundationdns.com: "2026.10.0"; blue.foundationdns.net: "2026.10.0"; blue.foundationdns.org: "2026.10.0". Hide or replace the version string.
    #17
  • ✓ Zone transfers refused #18
    No nameserver allows a zone transfer to the public.
  • ✓ TCP supported #19
    All nameservers answer over TCP.
  • ✓ EDNS supported #20
    All nameservers support EDNS(0).
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

pass

serial 2416765882 · primary blue.foundationdns.com

Found

Primary (MNAME)
blue.foundationdns.com
Contact (RNAME)
dns.cloudflare.com
Serial
2416765882
Refresh / retry
10000 s / 2400 s
Expire
604800 s
Negative TTL
1800 s

Serial per nameserver

NameserverSerial
blue.foundationdns.com (108.162.198.1)2416765882
blue.foundationdns.com (162.159.60.1)2416765882
blue.foundationdns.com (172.64.40.1)2416765882
blue.foundationdns.com (2606:4700:57::6ca2:c601)2416765882
blue.foundationdns.com (2a06:98c1:56::ac40:2801)2416765882
blue.foundationdns.com (2803:f800:52::a29f:3c01)2416765882
blue.foundationdns.net (108.162.198.31)2416765882
blue.foundationdns.net (162.159.60.31)2416765882
blue.foundationdns.net (172.64.40.31)2416765882
blue.foundationdns.net (2606:4700:57::6ca2:c61f)2416765882
blue.foundationdns.net (2803:f800:52::a29f:3c1f)2416765882
blue.foundationdns.net (2a06:98c1:56::ac40:281f)2416765882
blue.foundationdns.org (108.162.198.61)2416765882
blue.foundationdns.org (162.159.60.61)2416765882
blue.foundationdns.org (172.64.40.61)2416765882
blue.foundationdns.org (2606:4700:57::6ca2:c63d)2416765882
blue.foundationdns.org (2803:f800:52::a29f:3c3d)2416765882
blue.foundationdns.org (2a06:98c1:56::ac40:283d)2416765882

Checks

  • ✓ Serial 2416765882 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 2h46m40s, retry 40m, expire 7d, negative TTL 30m.
  • ✓ Primary is a public nameserver #24
    The primary nameserver blue.foundationdns.com is one of the listed nameservers.
  • ✓ Contact dns@cloudflare.com #25
    The SOA RNAME dns.cloudflare.com means dns@cloudflare.com.
  • ✓ Timestamp serial #26
    The serial 2416765882 is a Unix timestamp (2046-08-01 19:51 UTC).

DNSSEC

pass

Signed, DS published at parent

Found

Validated by resolver
yes
Signatures valid until
22 October 2026

DS at the parent

Key tagAlgorithmDigestMatches a key
2371ECDSAP256SHA256 (13)SHA256 937F274E43BBA130…yes

DNSKEY in the zone

Key tagRoleAlgorithm
2371KSK (257)ECDSAP256SHA256 (13)
34505ZSK (256)ECDSAP256SHA256 (13)

Checks

  • ✓ Signed and validated #27
    The zone is signed, the parent publishes a DS record, and the resolver validates the answers.
  • ✓ DS matches a key #28
    The DS record at the parent matches a key in the zone: key tag 2371 (SHA256).
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • ✓ Short-lived signatures (online signing) #30
    Signatures are valid for 50h0m0s and created on demand; the current one was made at 2026-10-20 21:41 UTC and expires at 2026-10-22 23:41 UTC.

Records

info

20 records at the apex

Found

Read from
108.162.198.1:53
TypeValueTTL
SOAblue.foundationdns.com. dns.cloudflare.com. 2416765882 10000 2400 604800 18001800
NSblue.foundationdns.com.300
NSblue.foundationdns.net.300
NSblue.foundationdns.org.300
A104.18.26.13300
A104.18.27.13300
AAAA2606:4700::6812:1a0d300
AAAA2606:4700::6812:1b0d300
MX1 aspmx.l.google.com.300
MX10 alt3.aspmx.l.google.com.300
MX10 alt4.aspmx.l.google.com.300
MX5 alt1.aspmx.l.google.com.300
MX5 alt2.aspmx.l.google.com.300
TXT"apple-domain-verification=KoQb8xXwjbbId63G"3600
TXT"facebook-domain-verification=bgtaqb5kj6r8to7vuxtcaebh0oxucl"3600
TXT"google-site-verification=I_b3lSlZfCzL-N8iA0jndlRijm5vzSkTYFT-xzUeYBw"3600
TXT"google-site-verification=bfqqSsiMfhSAjuEZ4FvtCJioNHpi_sJfqEIw50m0qbE"3600
TXT"google-site-verification=sbcS_e5EiMNiBl5fwG46GGwFHlRu9Y5Z1gS1aEFlYqI"3600
TXT"google-site-verification=xRlg_xtmGpEf3UylOE5OKKprjiJ7oY9h9UoNqzSMp-0"3600
TXT"v=spf1 include:_spf.google.com include:mail.zendesk.com include:_spf.salesforce.com ip4:50.115.216.34 ~all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, AAAA 5m, MX 5m, NS 5m. The NS TTL at the parent is 1d and in the zone 5m; resolvers may use either.
  • ✓ No CNAME at the apex #33
    The zone apex has no CNAME record.
  • i
    Wildcard record
    A random name under the zone resolves, so there is a wildcard (*) record. Typos and non-existent hosts resolve too, which can confuse mail and certificate checks.
    #34
  • i
    No CAA records
    Without CAA records any certificate authority may issue certificates for this domain. A CAA record limits issuance to the CAs you use.
    #35