safaribooksonline.com

Checked 22 October 2026, 10:33 UTC · via 8.8.8.8
!Passed with warnings
23 passed 5 warnings 0 failed 3 info

Registration

info

.com generic · GoDaddy.com, LLC · expires 2027-03-16

Found

TLD
.com (generic)
ICANN policies apply
yes
Registrar
GoDaddy.com, LLC
Registered
17 March 2001
Last changed
4 March 2026
Expires
16 March 2027
Status
client delete prohibited, client renew prohibited, client transfer prohibited, client update prohibited
Registry nameservers
a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net, a3-67.akam.net, a4-64.akam.net
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 2027-03-16 #3
    The registration is valid until 2027-03-16 (145 days).
  • ✓ Transfer locked #4
    Registry status: client delete prohibited, client renew prohibited, client transfer prohibited, client update prohibited.
  • ✓ Registry and delegation match #5
    The nameservers registered at the registry are the ones published in DNS.

Delegation

warn

a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net, a3-67.akam.net, a4-64.akam.net

Found

Parent zone
com
Delegation from
a.gtld-servers.net (192.5.6.30)
NS at the parent
a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net, a3-67.akam.net, a4-64.akam.net
NS in the zone
a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net
NameserverAddressesNetwork (AS)Glue
a1-225.akam.net193.108.91.225 2600:1401:2::e1AS20940 AKAMAI-ASN1 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a13-64.akam.net2.22.230.64 2600:1480:800::40AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a16-65.akam.net23.211.132.65 2600:1406:1b::41AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a20-66.akam.net95.100.175.66 2a02:26f0:67::42AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a3-67.akam.net (parent only)96.7.49.67 2600:1408:1c::43AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-
a4-64.akam.net (parent only)72.246.46.64 2600:1480:9000::40AS21342 AKAMAI-ASN2 - Akamai International B.V., NL AS21342 AKAMAI-ASN2 - Akamai International B.V., NL-

Checks

  • ✓ 6 nameservers #6
    Delegated to a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net, a3-67.akam.net, a4-64.akam.net.
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only at the parent: a3-67.akam.net, a4-64.akam.net. a1-225.akam.net, a13-64.akam.net, a16-65.akam.net, a20-66.akam.net, a3-67.akam.net, a4-64.akam.net report NS a1-225.akam.net a13-64.akam.net a16-65.akam.net a20-66.akam.net.
    #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 6 IPv4 /24s and 6 IPv6 /48s.
  • ✓ 2 autonomous systems #11
    The nameservers are spread over: AS20940 (AKAMAI-ASN1 - Akamai International B.V., NL): 1 address; AS21342 (AKAMAI-ASN2 - Akamai International B.V., NL): 11 addresses.
  • i
    All nameserver names under .net
    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

12 of 12 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
a1-225.akam.net 193.108.91.225NOERROR, 4 ms, authoritativenoyes / yesrefused41824.6
a1-225.akam.net 2600:1401:2::e1NOERROR, 4 ms, authoritativenoyes / yesrefused41824.4
a13-64.akam.net 2.22.230.64NOERROR, 4 ms, authoritativenoyes / yesrefused41824.7
a13-64.akam.net 2600:1480:800::40NOERROR, 4 ms, authoritativenoyes / yesrefused41824.11
a16-65.akam.net 23.211.132.65NOERROR, 4 ms, authoritativenoyes / yesrefused48878.29
a16-65.akam.net 2600:1406:1b::41NOERROR, 4 ms, authoritativenoyes / yesrefused48878.33
a20-66.akam.net 95.100.175.66NOERROR, 6 ms, authoritativenoyes / yesrefused48878.30
a20-66.akam.net 2a02:26f0:67::42NOERROR, 4 ms, authoritativenoyes / yesrefused48878.27
a3-67.akam.net 96.7.49.67NOERROR, 3 ms, authoritativenoyes / yesrefused41824.8
a3-67.akam.net 2600:1408:1c::43NOERROR, 5 ms, authoritativenoyes / yesrefused41824.11
a4-64.akam.net 72.246.46.64NOERROR, 3 ms, authoritativenoyes / yesrefused48878.30
a4-64.akam.net 2600:1480:9000::40NOERROR, 3 ms, authoritativenoyes / yesrefused48878.26

Checks

  • ✓ All respond #14
    All 12 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: a1-225.akam.net: "41824.6"; a1-225.akam.net: "41824.4"; a13-64.akam.net: "41824.7"; a13-64.akam.net: "41824.11"; a16-65.akam.net: "48878.29"; a16-65.akam.net: "48878.33"; a20-66.akam.net: "48878.30"; a20-66.akam.net: "48878.27"; a3-67.akam.net: "41824.8"; a3-67.akam.net: "41824.11"; a4-64.akam.net: "48878.30"; a4-64.akam.net: "48878.26". 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 2021062422 · primary a1-225.akam.net

Found

Primary (MNAME)
a1-225.akam.net
Contact (RNAME)
nic-tc.oreilly.com
Serial
2021062422
Refresh / retry
600 s / 1800 s
Expire
5184000 s
Negative TTL
3600 s

Serial per nameserver

NameserverSerial
a1-225.akam.net (193.108.91.225)2021062422
a1-225.akam.net (2600:1401:2::e1)2021062422
a13-64.akam.net (2.22.230.64)2021062422
a13-64.akam.net (2600:1480:800::40)2021062422
a16-65.akam.net (23.211.132.65)2021062422
a16-65.akam.net (2600:1406:1b::41)2021062422
a20-66.akam.net (95.100.175.66)2021062422
a20-66.akam.net (2a02:26f0:67::42)2021062422
a3-67.akam.net (96.7.49.67)2021062422
a3-67.akam.net (2600:1408:1c::43)2021062422
a4-64.akam.net (72.246.46.64)2021062422
a4-64.akam.net (2600:1480:9000::40)2021062422

Checks

  • ✓ Serial 2021062422 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    refresh 10m is outside 20m–1d; retry 30m should be shorter than refresh 10m. Current values: refresh 10m, retry 30m, expire 60d, negative TTL 1h.
    #23
  • ✓ Primary is a public nameserver #24
    The primary nameserver a1-225.akam.net is one of the listed nameservers.
  • ✓ Contact nic-tc@oreilly.com #25
    The SOA RNAME nic-tc.oreilly.com means nic-tc@oreilly.com.
  • ✓ Date-based serial #26
    The serial 2021062422 follows the YYYYMMDDnn convention (2021-06-24).

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

16 records at the apex

Found

Read from
193.108.91.225:53
TypeValueTTL
SOAa1-225.akam.net. nic-tc.oreilly.com. 2021062422 600 1800 5184000 36003600
NSa20-66.akam.net.86400
NSa1-225.akam.net.86400
NSa13-64.akam.net.86400
NSa16-65.akam.net.86400
A34.169.83.16760
MX20 alt1.aspmx.l.google.com.3600
MX10 aspmx.l.google.com.3600
MX30 alt4.aspmx.l.google.com.3600
MX30 alt3.aspmx.l.google.com.3600
MX20 alt2.aspmx.l.google.com.3600
TXT"_globalsign-domain-verification=GXpUUS49HB9rYWZEmxJFtZdS61weLMlf91w9Dn-5O0"1800
TXT"v=spf1 mx ptr include:_spf.google.com include:salesforce.com include:atlassian.net include:_netblocks.google.com include:mcsignup.com ip4:50.17.197.101/32 ip4:184.23.159.64/26 ip4:50.56.121.228 ip4:216.74.39.32/27 ip4:193.194.158.0/24 -all"1800
TXT"87s19oj3j3tncvli1q22j6000k"1800
TXT"google-site-verification=BPWhjvTJaFF7Nq4tQLfSLrrK96MqdZhpX2nnuNSZfEw"1800
TXT"google-site-verification=jNmxfIA1iCCWsGequ2kqRNd1XdhR8JRUdvGL6cPofk0"1800

Checks

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