books.google.com

Zone google.com · Checked 22 October 2026, 08:02 UTC · via 8.8.8.8
!Passed with warnings
25 passed 2 warnings 0 failed 4 info

Registration

info

.com generic · MarkMonitor Inc. · expires 2028-09-14

Found

TLD
.com (generic)
ICANN policies apply
yes
Registrar
MarkMonitor Inc.
Registered
15 September 1997
Last changed
9 September 2019
Expires
14 September 2028
Status
client delete prohibited, client transfer prohibited, client update prohibited, server delete prohibited, server transfer prohibited, server update prohibited
Registry nameservers
ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com
RDAP server
https://rdap.verisign.com/com/v1/

Checks

  • i
    .com is a generic TLD (gTLD)
    Generic TLD under an ICANN registry agreement: ICANN-accredited registrars, UDRP and RDAP apply.
    #1
  • ✓ TLD delegated and signed #2
    .com is delegated in the root zone and DNSSEC-signed.
  • ✓ Expires on 2028-09-14 #3
    The registration is valid until 2028-09-14 (692 days).
  • ✓ Transfer locked #4
    Registry status: client delete prohibited, client transfer prohibited, client update prohibited, server delete prohibited, server transfer prohibited, server update prohibited.
  • ✓ Registry and delegation match #5
    The nameservers registered at the registry are the ones published in DNS.

Delegation

info

ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com

Found

Parent zone
com
Delegation from
a.gtld-servers.net (192.5.6.30)
NS at the parent
ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com
NS in the zone
ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com
NameserverAddressesNetwork (AS)Glue
ns1.google.com216.239.32.10 2001:4860:4802:32::aAS15169 GOOGLE - Google LLC, US AS15169 GOOGLE - Google LLC, US2001:4860:4802:32::a 216.239.32.10
ns2.google.com216.239.34.10 2001:4860:4802:34::aAS15169 GOOGLE - Google LLC, US AS15169 GOOGLE - Google LLC, US2001:4860:4802:34::a 216.239.34.10
ns3.google.com216.239.36.10 2001:4860:4802:36::aAS15169 GOOGLE - Google LLC, US AS15169 GOOGLE - Google LLC, US2001:4860:4802:36::a 216.239.36.10
ns4.google.com216.239.38.10 2001:4860:4802:38::aAS15169 GOOGLE - Google LLC, US AS15169 GOOGLE - Google LLC, US2001:4860:4802:38::a 216.239.38.10

Checks

  • ✓ 4 nameservers #6
    Delegated to ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • ✓ Glue present and correct #8
    Glue is published for the nameservers inside the zone: ns1.google.com, ns2.google.com, ns3.google.com, ns4.google.com.
  • ✓ 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 2001:4860:4802::/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 (AS15169 (GOOGLE - Google LLC, US): 8 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 .com
    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

pass

8 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.google.com 216.239.32.10NOERROR, 11 ms, authoritativenoyes / yesrefused-
ns1.google.com 2001:4860:4802:32::aNOERROR, 15 ms, authoritativenoyes / yesrefused-
ns2.google.com 216.239.34.10NOERROR, 24 ms, authoritativenoyes / yesrefused-
ns2.google.com 2001:4860:4802:34::aNOERROR, 24 ms, authoritativenoyes / yesrefused-
ns3.google.com 216.239.36.10NOERROR, 10 ms, authoritativenoyes / yesrefused-
ns3.google.com 2001:4860:4802:36::aNOERROR, 15 ms, authoritativenoyes / yesrefused-
ns4.google.com 216.239.38.10NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns4.google.com 2001:4860:4802:38::aNOERROR, 7 ms, authoritativenoyes / yesrefused-

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.
  • ✓ No version disclosed #17
    The nameservers don't reveal their software version.
  • ✓ 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 1003797344 · primary ns1.google.com

Found

Primary (MNAME)
ns1.google.com
Contact (RNAME)
dns-admin.google.com
Serial
1003797344
Refresh / retry
900 s / 900 s
Expire
1800 s
Negative TTL
60 s

Serial per nameserver

NameserverSerial
ns1.google.com (216.239.32.10)1003797344
ns1.google.com (2001:4860:4802:32::a)1003797344
ns2.google.com (216.239.34.10)1003797344
ns2.google.com (2001:4860:4802:34::a)1003797344
ns3.google.com (216.239.36.10)1003797344
ns3.google.com (2001:4860:4802:36::a)1003797344
ns4.google.com (216.239.38.10)1003797344
ns4.google.com (2001:4860:4802:38::a)1003797344

Checks

  • ✓ Serial 1003797344 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    refresh 15m is outside 20m–1d; retry 15m should be shorter than refresh 15m; expire 30m is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 30m must be longer than refresh + retry; negative caching TTL (minimum) 1m is outside 5m–1d (RFC 2308 recommends 1–3 hours). Current values: refresh 15m, retry 15m, expire 30m, negative TTL 1m.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns1.google.com is one of the listed nameservers.
  • ✓ Contact dns-admin@google.com #25
    The SOA RNAME dns-admin.google.com means dns-admin@google.com.
  • ✓ Timestamp serial #26
    The serial 1003797344 is a Unix timestamp (2001-10-23 00:35 UTC).

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

34 records at the apex

Found

Read from
216.239.32.10:53
TypeValueTTL
SOAns1.google.com. dns-admin.google.com. 1003797344 900 900 1800 6060
NSns3.google.com.345600
NSns2.google.com.345600
NSns1.google.com.345600
NSns4.google.com.345600
A142.251.110.138300
A142.251.110.102300
A142.251.110.113300
A142.251.110.139300
A142.251.110.101300
A142.251.110.100300
AAAA2a00:1450:4001:c1f::66300
AAAA2a00:1450:4001:c1f::65300
AAAA2a00:1450:4001:c1f::64300
AAAA2a00:1450:4001:c1f::8b300
MX10 smtp.google.com.300
TXT"onetrust-domain-verification=0d477fe608074e6f9c12bca7826035cc"300
TXT"onetrust-domain-verification=6d685f1d41a94696ad7ef771f68993e0"300
TXT"google-site-verification=wD8N7i1JTNTkezJ49swvWW48f8_9xveREV4oB-0Hf5o"300
TXT"apple-domain-verification=30afIBcvSuDV2PLX"300
TXT"docusign=1b0a6754-49b1-4db5-8540-d2c12664b289"300
TXT"arcules-domain-verification=2R4t5G7nI6tRCo61lpxxbLksPYstxhGmtV75cpr8x9K"300
TXT"facebook-domain-verification=22rm551cu4k0ab0bxsw536tlds4h95"300
TXT"google-site-verification=4ibFUgB-wXLQ_S7vsXVomSTVamuOXBiVAzpR5IZ87D0"300
TXT"docusign=05958488-4752-4ef2-95eb-aa7ba8a3bd0e"300
TXT"_r4rd1pvwyrpi7sw4a3hzmw8e51yh9td"300
TXT"Z29vZ2xl"300
TXT"google-site-verification=TV9-DBe4R80X4v0M4U_bd_J9cpOJM0nikft0jAgjmsQ"300
TXT"v=spf1 include:_spf.google.com ~all"300
TXT"work-accounts-domain-verification=Tcj6JjIMZOw2KsSEw2Nt2rLae89tN6"300
TXT"MS=E4A68B9AB2BB9670BCE15412F62916164C0B20BB"300
TXT"globalsign-smime-dv=CDYX+XFHUw2wml6/Gb8+59BsH31KzUr6c1l2BPvqKX8="300
TXT"cisco-ci-domain-verification=47c38bc8c4b74b7233e9053220c1bbe76bcc1cd33c7acf7acd36cd6a5332004b"300
CAA0 issue "pki.goog"86400

Checks

  • ✓ TTLs within range #32
    TTLs: A 5m, AAAA 5m, MX 5m, NS 4d. The NS TTL at the parent is 2d and in the zone 4d; 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.goog.