sz-online.de

Checked 22 October 2026, 00:31 UTC · via 8.8.8.8
✗Problems found
18 passed 5 warnings 2 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

warn

ns0.niedersachsen.com, pns.dtag.de, secondary006.dtag.net

Found

Parent zone
de
Delegation from
a.nic.de (194.0.0.53)
NS at the parent
ns0.niedersachsen.com, pns.dtag.de, secondary006.dtag.net
NS in the zone
ns2.sz-online.de, pns.sz-online.de
NameserverAddressesNetwork (AS)Glue
ns0.niedersachsen.com (parent only)193.30.60.250AS3209 VODANET - Vodafone GmbH, DE-
ns2.sz-online.de (zone only)193.254.185.232AS25504 CRONON-AS - Vautron Rechenzentrum AG, DE-
pns.dtag.de (parent only)194.25.0.125 2003:40:8000::100AS3320 DTAG - Deutsche Telekom AG, DE AS3320 DTAG - Deutsche Telekom AG, DE194.25.0.125 2003:40:8000::100
pns.sz-online.de (zone only)195.74.47.32AS42197 DDV-AS - DDV Sachsen GmbH, DE-
secondary006.dtag.net (parent only)195.244.245.25 2a00:fa8:3:0:100:0:6:1AS5605 NETUSE - NetUSE AG, DE AS5605 NETUSE - NetUSE AG, DE-

Checks

  • ✓ 3 nameservers #6
    Delegated to ns0.niedersachsen.com, pns.dtag.de, secondary006.dtag.net.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only at the parent: ns0.niedersachsen.com, pns.dtag.de, secondary006.dtag.net; only in the zone: ns2.sz-online.de, pns.sz-online.de. ns0.niedersachsen.com, pns.dtag.de, secondary006.dtag.net report NS ns2.sz-online.de pns.sz-online.de.
    #7
  • ✓ 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 5 IPv4 /24s and 2 IPv6 /48s.
  • ✓ 5 autonomous systems #11
    The nameservers are spread over: AS25504 (CRONON-AS - Vautron Rechenzentrum AG, DE): 1 address; AS3209 (VODANET - Vodafone GmbH, DE): 1 address; AS3320 (DTAG - Deutsche Telekom AG, DE): 2 addresses; AS42197 (DDV-AS - DDV Sachsen GmbH, DE): 1 address; AS5605 (NETUSE - NetUSE AG, DE): 2 addresses.
  • ✓ Nameserver names under 3 TLDs #12
    Nameserver names use the TLDs .com, .de, .net.
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns0.niedersachsen.com, ns2.sz-online.de, pns.sz-online.de.
    #13

Nameservers

fail

5 of 7 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns0.niedersachsen.com 193.30.60.250NOERROR, 11 ms, authoritativenoyes / yesrefused9.20.29
ns2.sz-online.de 193.254.185.232REFUSED, 14 ms, NOT authoritativenono / yesrefused9.16.27-Debian
pns.dtag.de 194.25.0.125NOERROR, 9 ms, authoritativenoyes / yesrefusedDomainNameServer
pns.dtag.de 2003:40:8000::100NOERROR, 8 ms, authoritativenoyes / yesrefusedDomainNameServer
pns.sz-online.de 195.74.47.32REFUSED, 20 ms, NOT authoritativenono / yesrefusedNot Disclosed
secondary006.dtag.net 195.244.245.25NOERROR, 13 ms, authoritativenoyes / yesrefusedDomainNameServer
secondary006.dtag.net 2a00:fa8:3:0:100:0:6:1NOERROR, 17 ms, authoritativenoyes / yesrefusedDomainNameServer

Checks

  • ✓ All respond #14
    All 7 nameserver addresses answered.
  • ✗
    Lame delegation
    These nameservers don't answer authoritatively for the zone, so resolvers ignore them: ns2.sz-online.de (193.254.185.232): REFUSED, authoritative=false; pns.sz-online.de (195.74.47.32): 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: ns0.niedersachsen.com: "9.20.29"; ns2.sz-online.de: "9.16.27-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: ns2.sz-online.de (193.254.185.232): ; pns.sz-online.de (195.74.47.32): .
    #19
  • ✓ EDNS supported #20
    All nameservers support EDNS(0).
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

warn

serial 2026101941 · primary pns.sz-online.de

Found

Primary (MNAME)
pns.sz-online.de
Contact (RNAME)
dns.gutenberg-rz.de
Serial
2026101941
Refresh / retry
14400 s / 3600 s
Expire
1814400 s
Negative TTL
120 s

Serial per nameserver

NameserverSerial
ns0.niedersachsen.com (193.30.60.250)2026101941
pns.dtag.de (194.25.0.125)2026101941
pns.dtag.de (2003:40:8000::100)2026101941
secondary006.dtag.net (195.244.245.25)2026101941
secondary006.dtag.net (2a00:fa8:3:0:100:0:6:1)2026101941

Checks

  • ✓ Serial 2026101941 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    negative caching TTL (minimum) 2m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 4h, retry 1h, expire 21d, negative TTL 2m.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver pns.sz-online.de is one of the listed nameservers.
  • ✓ Contact dns@gutenberg-rz.de #25
    The SOA RNAME dns.gutenberg-rz.de means dns@gutenberg-rz.de.
  • ✓ Date-based serial #26
    The serial 2026101941 follows the YYYYMMDDnn convention (2026-10-19).

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
193.30.60.250:53
TypeValueTTL
SOApns.sz-online.de. dns.gutenberg-rz.de. 2026101941 14400 3600 1814400 120120
NSns2.sz-online.de.120
NSpns.sz-online.de.120
A193.30.60.245120
MX10 szonline-de0e.mail.protection.outlook.com.120
TXT"facebook-domain-verification=mamtm5hm8qdbtq078ns4doe3tfd7ie"120
TXT"v=spf1 ip4:195.74.44.0/22 ip4:172.16.0.0/12 include:spf.protection.outlook.com -all"120
TXT"google-site-verification=6fQQxA43wUBFrwwWoVBfdZuoXtpW57aCgybHxJ0kIj4"120
TXT"vmc4ounc3e3gplmi7veush7cba"120
TXT"MS=ms11970741"120
TXT"02uea9CtAHmROjgXKbv0j7OylIowPUY8vk4VnqsZy5grlZfseucauz9zhhF8UQM7kJwxys8PaDXwM1/b4AyDuw=="120

Checks

  • !
    Very low TTLs
    These records have a TTL below 5m, causing extra queries and slower lookups: A (2m), MX (2m), NS (2m). Low TTLs are useful just before a planned change. The NS TTL at the parent is 1d and in the zone 2m; 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