iserv.de

Checked 21 October 2026, 23:00 UTC · via 8.8.8.8
!Passed with warnings
21 passed 4 warnings 0 failed 4 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

ns1.iserv.eu, ns2.iserv.eu, ns3.iserv.eu, ns4.iserv.eu

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns1.iserv.eu, ns2.iserv.eu, ns3.iserv.eu, ns4.iserv.eu
NS in the zone
ns1.iserv.eu, ns2.iserv.eu, ns3.iserv.eu, ns4.iserv.eu
NameserverAddressesNetwork (AS)Glue
ns1.iserv.eu116.202.2.219 2a01:4f8:c01f:42::1AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
ns2.iserv.eu91.204.44.133 2a03:4000:20:19b::1AS197540 netcup-AS - netcup GmbH, DE AS197540 netcup-AS - netcup GmbH, DE-
ns3.iserv.eu116.203.7.41 2a01:4f8:1c0c:8111::1AS24940 HETZNER-AS - Hetzner Online GmbH, DE AS24940 HETZNER-AS - Hetzner Online GmbH, DE-
ns4.iserv.eu188.68.45.203 2a03:4000:20:19e::1AS197540 netcup-AS - netcup GmbH, DE AS197540 netcup-AS - netcup GmbH, DE-

Checks

  • ✓ 4 nameservers #6
    Delegated to ns1.iserv.eu, ns2.iserv.eu, ns3.iserv.eu, ns4.iserv.eu.
  • ✓ 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 4 IPv4 /24s and 3 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS197540 (netcup-AS - netcup GmbH, DE): 4 addresses; AS24940 (HETZNER-AS - Hetzner Online GmbH, DE): 4 addresses.
  • i
    All nameserver names under .eu
    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

warn

8 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.iserv.eu 116.202.2.219NOERROR, 6 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns1.iserv.eu 2a01:4f8:c01f:42::1NOERROR, 5 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns2.iserv.eu 91.204.44.133NOERROR, 1 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns2.iserv.eu 2a03:4000:20:19b::1NOERROR, 1 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns3.iserv.eu 116.203.7.41NOERROR, 3 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns3.iserv.eu 2a01:4f8:1c0c:8111::1NOERROR, 2 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns4.iserv.eu 188.68.45.203NOERROR, 4 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian
ns4.iserv.eu 2a03:4000:20:19e::1NOERROR, 3 ms, authoritativenoyes / yesrefused9.18.49-1~deb12u2-Debian

Checks

  • ✓ All respond #14
    All 8 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: ns1.iserv.eu: "9.18.49-1~deb12u2-Debian"; ns2.iserv.eu: "9.18.49-1~deb12u2-Debian"; ns3.iserv.eu: "9.18.49-1~deb12u2-Debian"; ns4.iserv.eu: "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.
  • ✓ 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 371591958 · primary ns1.iserv.eu

Found

Primary (MNAME)
ns1.iserv.eu
Contact (RNAME)
hostmaster.iserv.eu
Serial
371591958
Refresh / retry
86400 s / 10800 s
Expire
3600000 s
Negative TTL
60 s

Serial per nameserver

NameserverSerial
ns1.iserv.eu (116.202.2.219)371591958
ns1.iserv.eu (2a01:4f8:c01f:42::1)371591958
ns2.iserv.eu (91.204.44.133)371591958
ns2.iserv.eu (2a03:4000:20:19b::1)371591958
ns3.iserv.eu (116.203.7.41)371591958
ns3.iserv.eu (2a01:4f8:1c0c:8111::1)371591958
ns4.iserv.eu (188.68.45.203)371591959
ns4.iserv.eu (2a03:4000:20:19e::1)371591959

Checks

  • !
    Serials differ
    The nameservers serve different versions of the zone: 371591958 on ns1.iserv.eu (116.202.2.219), ns1.iserv.eu (2a01:4f8:c01f:42::1), ns2.iserv.eu (91.204.44.133), ns2.iserv.eu (2a03:4000:20:19b::1), ns3.iserv.eu (116.203.7.41), ns3.iserv.eu (2a01:4f8:1c0c:8111::1); 371591959 on ns4.iserv.eu (188.68.45.203), ns4.iserv.eu (2a03:4000:20:19e::1). This is normal for a few minutes after a change; if it lasts, zone transfers to the secondaries are failing.
    #22
  • !
    Unusual SOA timers
    negative caching TTL (minimum) 1m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 1d, retry 3h, expire 1000h, negative TTL 1m.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.iserv.eu is one of the listed nameservers.
  • ✓ Contact hostmaster@iserv.eu #25
    The SOA RNAME hostmaster.iserv.eu means hostmaster@iserv.eu.
  • ✓ Counter serial #26
    The serial 371591958 is a plain counter.

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

info

17 records at the apex

Found

Read from
116.202.2.219:53
TypeValueTTL
SOAns1.iserv.eu. hostmaster.iserv.eu. 371591958 86400 10800 3600000 603600
NSns4.iserv.eu.3600
NSns3.iserv.eu.3600
NSns1.iserv.eu.3600
NSns2.iserv.eu.3600
A188.68.60.9600
A116.202.2.255600
A116.203.121.185600
AAAA2a01:4f8:c0c:ae45::1600
AAAA2a03:4000:1b:738::1600
AAAA2a01:4f8:c01f:4a::1600
MX10 iserv.iserv.eu.3600
MX50 offline.iserv.eu.3600
TXT"openai-domain-verification=dv-UZOuHIlTppw4SsB1lnUNC6Hk"3600
TXT"google-site-verification=fjJnEwEm6ZB_0NwWRVBx8hJWvZ6ykJEUWuAQA6Xl6dY"3600
TXT"jetbrains-domain-verification=b8mthhivdb3clwdv3hafplyxo"3600
TXT"v=spf1 a mx a:relay1.iserv.eu a:relay2.iserv.eu a:relay3.iserv.eu a:relaybs.iserv.eu include:_spf.inwx.net ?all"3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, AAAA 10m, 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.
  • 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