hs-bremen.de

Checked 21 October 2026, 22:51 UTC · via 8.8.8.8
✗Problems found
21 passed 3 warnings 2 failed 3 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

warn

dns-2.dfn.de, dns.hs-bremen.de, dns1.belwue.de, dns2.hs-bremen.de

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
dns-2.dfn.de, dns.hs-bremen.de, dns1.belwue.de, dns2.hs-bremen.de
NS in the zone
dns-2.dfn.de, dns.hs-bremen.de, dns2.hs-bremen.de
NameserverAddressesNetwork (AS)Glue
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.hs-bremen.de194.94.24.34 2001:638:703:2::34AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE194.94.24.34 2001:638:703:2::34
dns1.belwue.de (parent only)129.143.2.10 2001:7c0::53:10AS553 BELWUE - Universitaet Stuttgart, DE AS553 BELWUE - Universitaet Stuttgart, DE129.143.2.10 2001:7c0::53:10
dns2.hs-bremen.de194.94.24.10 2001:638:703:2::10AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE AS680 DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE194.94.24.10 2001:638:703:2::10

Checks

  • ✓ 4 nameservers #6
    Delegated to dns-2.dfn.de, dns.hs-bremen.de, dns1.belwue.de, dns2.hs-bremen.de.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only at the parent: dns1.belwue.de. dns-2.dfn.de, dns.hs-bremen.de, dns2.hs-bremen.de report NS dns-2.dfn.de dns.hs-bremen.de dns2.hs-bremen.de.
    #7
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: dns.hs-bremen.de, dns2.hs-bremen.de.
  • ✓ 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.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS553 (BELWUE - Universitaet Stuttgart, DE): 2 addresses; AS680 (DFN - Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE): 6 addresses.
  • 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
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

fail

6 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
dns-2.dfn.de 193.174.75.54NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns-2.dfn.de 2001:638:d:b102::1NOERROR, 7 ms, authoritativenoyes / yesrefused0
dns.hs-bremen.de 194.94.24.34NOERROR, 11 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
dns.hs-bremen.de 2001:638:703:2::34NOERROR, 13 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
dns1.belwue.de 129.143.2.10REFUSED, 7 ms, NOT authoritativenono / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns1.belwue.de 2001:7c0::53:10REFUSED, 7 ms, NOT authoritativenono / yesrefusedPowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)
dns2.hs-bremen.de 194.94.24.10NOERROR, 12 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
dns2.hs-bremen.de 2001:638:703:2::10NOERROR, 13 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian

Checks

  • ✓ All respond #14
    All 8 nameserver addresses answered.
  • ✗
    Lame delegation
    These nameservers don't answer authoritatively for the zone, so resolvers ignore them: dns1.belwue.de (129.143.2.10): REFUSED, authoritative=false; dns1.belwue.de (2001:7c0::53:10): REFUSED, authoritative=false.
    #15
  • ✓ 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: dns.hs-bremen.de: "9.18.49-1~deb12u2-Debian"; dns1.belwue.de: "PowerDNS Authoritative Server 4.5.5 (built Dec 8 2022 18:24:18 by root@a309361b6303)"; dns2.hs-bremen.de: "9.18.49-1~deb12u2-Debian". Hide or replace the version string.
    #17
  • ✓ Zone transfers refused #18
    No nameserver allows a zone transfer to the public.
  • ✗
    No DNS over TCP
    DNS over TCP is required (RFC 7766); without it, large answers such as DNSSEC responses fail. Not answering over TCP: dns1.belwue.de (129.143.2.10): ; dns1.belwue.de (2001:7c0::53:10): .
    #19
  • ✓ EDNS supported #20
    All nameservers support EDNS(0).
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

pass

serial 2026102103 · primary dns.hs-bremen.de

Found

Primary (MNAME)
dns.hs-bremen.de
Contact (RNAME)
hostmaster.hs-bremen.de
Serial
2026102103
Refresh / retry
21600 s / 3600 s
Expire
2592000 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
dns-2.dfn.de (193.174.75.54)2026102103
dns-2.dfn.de (2001:638:d:b102::1)2026102103
dns.hs-bremen.de (194.94.24.34)2026102103
dns.hs-bremen.de (2001:638:703:2::34)2026102103
dns2.hs-bremen.de (194.94.24.10)2026102103
dns2.hs-bremen.de (2001:638:703:2::10)2026102103

Checks

  • ✓ Serial 2026102103 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 6h, retry 1h, expire 30d, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver dns.hs-bremen.de is one of the listed nameservers.
  • ✓ Contact hostmaster@hs-bremen.de #25
    The SOA RNAME hostmaster.hs-bremen.de means hostmaster@hs-bremen.de.
  • ✓ Date-based serial #26
    The serial 2026102103 follows the YYYYMMDDnn convention (2026-10-21).

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

pass

14 records at the apex

Found

Read from
193.174.75.54:53
TypeValueTTL
SOAdns.hs-bremen.de. hostmaster.hs-bremen.de. 2026102103 21600 3600 2592000 864003600
NSdns.hs-bremen.de.3600
NSdns2.hs-bremen.de.3600
NSdns-2.dfn.de.3600
A194.94.24.2123600
MX10 fmail3.hs-bremen.de.3600
MX10 fmail2.hs-bremen.de.3600
MX10 fmail1.hs-bremen.de.3600
TXT"google-site-verification=_3iNhFn6uX4cY23yqTxB78Tk7cDz38mYmd2Rn0mip88"3600
TXT"v=spf1 ip4:194.94.24.0/26 ip6:2001:638:703:2::/64 mx include:_spf.zimpel.de ?all"3600
CAA0 issue "pki.dfn.de"3600
CAA0 issue "sectigo.com"3600
CAA0 issue "harica.gr"3600
CAA0 issue "letsencrypt.org"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 1h, MX 1h, NS 1h. The NS TTL at the parent is 1d and in the zone 1h; resolvers may use either.
  • ✓ No CNAME at the apex #33
    The zone apex has no CNAME record.
  • ✓ No wildcard #34
    Names that don't exist return NXDOMAIN.
  • ✓ CAA restricts issuance #35
    Certificates may be issued by: pki.dfn.de, sectigo.com, harica.gr, letsencrypt.org.