ptj.de

Checked 21 October 2026, 23:51 UTC · via 8.8.8.8
!Passed with warnings
18 passed 3 warnings 0 failed 8 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

dns-1.dfn.de, dns-1.fz-juelich.de, dns-2.dfn.de, dns-2.fz-juelich.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-1.dfn.de, dns-1.fz-juelich.de, dns-2.dfn.de, dns-2.fz-juelich.de
NS in the zone
dns-1.dfn.de, dns-1.fz-juelich.de, dns-2.dfn.de, dns-2.fz-juelich.de
NameserverAddressesNetwork (AS)Glue
dns-1.dfn.de193.174.75.50 2001:638:d:b101::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
dns-1.fz-juelich.de134.94.105.2AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.94.105.2
dns-2.dfn.de193.174.75.54 2001:638:d:b102::1AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE-
dns-2.fz-juelich.de134.94.105.3AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE134.94.105.3

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-1.dfn.de, dns-1.fz-juelich.de, dns-2.dfn.de, dns-2.fz-juelich.de.
  • ✓ 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.
  • i
    One address family in one network
    all IPv6 addresses are in 2001:638:d::/48, while the other address family is spread over several networks.
    #10
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 6 addresses). An outage or attack on that network affects all nameservers; large anycast providers mitigate this, but a secondary DNS provider adds independence.
    #11
  • i
    All nameserver names under .de
    All nameserver names are under one TLD, so a problem with that TLD also makes the nameservers unreachable. Some operators use names under two TLDs for extra resilience.
    #12
  • i
    Partly IPv6
    These nameservers have no IPv6 address: dns-1.fz-juelich.de, dns-2.fz-juelich.de.
    #13

Nameservers

info

6 of 6 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-1.dfn.de 193.174.75.50NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-1.dfn.de 2001:638:d:b101::1NOERROR, 14 ms, authoritativenoyes / yesrefused0
dns-1.fz-juelich.de 134.94.105.2NOERROR, 7 ms, authoritativenoyes / yesrefused-
dns-2.dfn.de 193.174.75.54NOERROR, 6 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 2001:638:d:b102::1NOERROR, 6 ms, authoritativenoyes / yesrefused0
dns-2.fz-juelich.de 134.94.105.3NOERROR, 7 ms, authoritativenoyes / yesrefused-

Checks

  • ✓ All respond #14
    All 6 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.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: dns-1.dfn.de: "0"; dns-2.dfn.de: "0".
    #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

warn

serial 2023110200 · primary dns-1.fz-juelich.de

Found

Primary (MNAME)
dns-1.fz-juelich.de
Contact (RNAME)
hostmaster.fz-juelich.de
Serial
2023110200
Refresh / retry
1800 s / 3600 s
Expire
1209600 s
Negative TTL
1800 s

Serial per nameserver

NameserverSerial
dns-1.dfn.de (193.174.75.50)2023110200
dns-1.dfn.de (2001:638:d:b101::1)2023110200
dns-1.fz-juelich.de (134.94.105.2)2023110200
dns-2.dfn.de (193.174.75.54)2023110200
dns-2.dfn.de (2001:638:d:b102::1)2023110200
dns-2.fz-juelich.de (134.94.105.3)2023110200

Checks

  • ✓ Serial 2023110200 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    retry 1h should be shorter than refresh 30m. Current values: refresh 30m, retry 1h, expire 14d, negative TTL 30m.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns-1.fz-juelich.de is one of the listed nameservers.
  • ✓ Contact hostmaster@fz-juelich.de #25
    The SOA RNAME hostmaster.fz-juelich.de means hostmaster@fz-juelich.de.
  • ✓ Date-based serial #26
    The serial 2023110200 follows the YYYYMMDDnn convention (2023-11-02).

DNSSEC

warn

Not signed

Found

Validated by resolver
no

Checks

  • !
    Not signed
    The zone is not signed with DNSSEC, so answers can be spoofed. Enable DNSSEC at your DNS provider and publish the DS record at your registrar.
    #27

Records

warn

11 records at the apex

Found

Read from
193.174.75.50:53
TypeValueTTL
SOAdns-1.fz-juelich.de. hostmaster.fz-juelich.de. 2023110200 1800 3600 1209600 180021600
NSdns-1.dfn.de.21600
NSdns-2.fz-juelich.de.21600
NSdns-2.dfn.de.21600
NSdns-1.fz-juelich.de.21600
A134.94.131.18821600
MX10 mailgw-k01.its.kfa-juelich.de.60
MX10 mailgw-e01.its.kfa-juelich.de.60
TXT"protonmail-verification=5195a1ee1c66a89d05d59fab88b5a9c918756f3a"60
TXT"asv=fd5118d2dc6fcb8cf96cf3f6ef668aa0"60
TXT"v=spf1 include:fz-juelich.de mx ~all"60

Checks

  • !
    Very low TTLs
    These records have a TTL below 5m, causing extra queries and slower lookups: MX (1m). Low TTLs are useful just before a planned change. The NS TTL at the parent is 1d and in the zone 6h; resolvers may use either.
    #32
  • ✓ No CNAME at the apex #33
    The zone apex has no CNAME record.
  • ✓ No wildcard #34
    Names that don't exist return NXDOMAIN.
  • 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