teamtreehouse.com

Checked 22 October 2026, 10:55 UTC · via 8.8.8.8
!Passed with warnings
29 passed 2 warnings 0 failed 3 info

Registration

info

.com generic · NameCheap, Inc. · expires 2027-03-22

Found

TLD
.com (generic)
ICANN policies apply
yes
Registrar
NameCheap, Inc.
Registered
22 March 2011
Last changed
20 February 2026
Expires
22 March 2027
Status
client transfer prohibited
Registry nameservers
ns-1004.awsdns-61.net, ns-1233.awsdns-26.org, ns-1567.awsdns-03.co.uk, ns-334.awsdns-41.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 2027-03-22 #3
    The registration is valid until 2027-03-22 (150 days).
  • ✓ Transfer locked #4
    Registry status: client transfer prohibited.
  • ✓ Registry and delegation match #5
    The nameservers registered at the registry are the ones published in DNS.

Delegation

info

ns-1004.awsdns-61.net, ns-1233.awsdns-26.org, ns-1567.awsdns-03.co.uk, ns-334.awsdns-41.com

Found

Parent zone
com
Delegation from
a.gtld-servers.net (192.5.6.30)
NS at the parent
ns-1004.awsdns-61.net, ns-1233.awsdns-26.org, ns-1567.awsdns-03.co.uk, ns-334.awsdns-41.com
NS in the zone
ns-1004.awsdns-61.net, ns-1233.awsdns-26.org, ns-1567.awsdns-03.co.uk, ns-334.awsdns-41.com
NameserverAddressesNetwork (AS)Glue
ns-1004.awsdns-61.net205.251.195.236 2600:9000:5303:ec00::1AS16509 AMAZON-02 - Amazon.com, Inc., US AS16509 AMAZON-02 - Amazon.com, Inc., US-
ns-1233.awsdns-26.org205.251.196.209 2600:9000:5304:d100::1AS16509 AMAZON-02 - Amazon.com, Inc., US AS16509 AMAZON-02 - Amazon.com, Inc., US-
ns-1567.awsdns-03.co.uk205.251.198.31 2600:9000:5306:1f00::1AS16509 AMAZON-02 - Amazon.com, Inc., US AS16509 AMAZON-02 - Amazon.com, Inc., US-
ns-334.awsdns-41.com205.251.193.78 2600:9000:5301:4e00::1AS16509 AMAZON-02 - Amazon.com, Inc., US AS16509 AMAZON-02 - Amazon.com, Inc., US205.251.193.78 2600:9000:5301:4e00::1

Checks

  • ✓ 4 nameservers #6
    Delegated to ns-1004.awsdns-61.net, ns-1233.awsdns-26.org, ns-1567.awsdns-03.co.uk, ns-334.awsdns-41.com.
  • ✓ 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 4 IPv6 /48s.
  • i
    All nameservers in one AS
    All nameserver addresses are announced by one network operator (AS16509 (AMAZON-02 - Amazon.com, Inc., 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
  • ✓ Nameserver names under 4 TLDs #12
    Nameserver names use the TLDs .com, .net, .org, .uk.
  • ✓ All reachable over IPv6 #13
    Every nameserver has an IPv6 address.

Nameservers

pass

8 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns-1004.awsdns-61.net 205.251.195.236NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns-1004.awsdns-61.net 2600:9000:5303:ec00::1NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns-1233.awsdns-26.org 205.251.196.209NOERROR, 3 ms, authoritativenoyes / yesrefused-
ns-1233.awsdns-26.org 2600:9000:5304:d100::1NOERROR, 4 ms, authoritativenoyes / yesrefused-
ns-1567.awsdns-03.co.uk 205.251.198.31NOERROR, 9 ms, authoritativenoyes / yesrefused-
ns-1567.awsdns-03.co.uk 2600:9000:5306:1f00::1NOERROR, 9 ms, authoritativenoyes / yesrefused-
ns-334.awsdns-41.com 205.251.193.78NOERROR, 9 ms, authoritativenoyes / yesrefused-
ns-334.awsdns-41.com 2600:9000:5301:4e00::1NOERROR, 9 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

pass

serial 1 · primary ns-334.awsdns-41.com

Found

Primary (MNAME)
ns-334.awsdns-41.com
Contact (RNAME)
awsdns-hostmaster.amazon.com
Serial
1
Refresh / retry
7200 s / 900 s
Expire
1209600 s
Negative TTL
86400 s

Serial per nameserver

NameserverSerial
ns-1004.awsdns-61.net (205.251.195.236)1
ns-1004.awsdns-61.net (2600:9000:5303:ec00::1)1
ns-1233.awsdns-26.org (205.251.196.209)1
ns-1233.awsdns-26.org (2600:9000:5304:d100::1)1
ns-1567.awsdns-03.co.uk (205.251.198.31)1
ns-1567.awsdns-03.co.uk (2600:9000:5306:1f00::1)1
ns-334.awsdns-41.com (205.251.193.78)1
ns-334.awsdns-41.com (2600:9000:5301:4e00::1)1

Checks

  • ✓ Serial 1 everywhere #22
    All nameservers serve the same version of the zone.
  • ✓ Timers within recommendations #23
    SOA refresh 2h, retry 15m, expire 14d, negative TTL 1d.
  • ✓ Primary is a public nameserver #24
    The primary nameserver ns-334.awsdns-41.com is one of the listed nameservers.
  • ✓ Contact awsdns-hostmaster@amazon.com #25
    The SOA RNAME awsdns-hostmaster.amazon.com means awsdns-hostmaster@amazon.com.
  • ✓ Counter serial #26
    The serial 1 is a plain counter.

DNSSEC

warn

Signed, but no DS at parent

Found

Validated by resolver
no
Denial of existence
NSEC
Signatures valid until
22 October 2026

DNSKEY in the zone

Key tagRoleAlgorithm
6211ZSK (256)ECDSAP256SHA256 (13)
33831ZSK (256)ECDSAP256SHA256 (13)
15387KSK (257)ECDSAP256SHA256 (13)

Checks

  • !
    Signed but not delegated securely
    The zone is signed but the parent has no DS record, so the signatures are not used. Publish the DS record at your registrar.
    #27
  • ✓ Modern algorithms #29
    Key algorithms: ECDSAP256SHA256 (13).
  • ✓ Short-lived signatures (online signing) #30
    Signatures are valid for 2h0m0s and created on demand; the current one was made at 2026-10-22 09:55 UTC and expires at 2026-10-22 12:10 UTC.
  • i
    NSEC
    The zone uses NSEC, so its full contents can be listed by walking the NSEC chain. That is fine unless the names are sensitive.
    #31

Records

warn

25 records at the apex

Found

Read from
205.251.195.236:53
TypeValueTTL
SOAns-334.awsdns-41.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400900
NSns-1004.awsdns-61.net.172800
NSns-1233.awsdns-26.org.172800
NSns-1567.awsdns-03.co.uk.172800
NSns-334.awsdns-41.com.172800
A3.220.17.19860
A32.194.79.6660
MX10 aspmx.l.google.com.300
MX20 alt1.aspmx.l.google.com.300
MX20 alt2.aspmx.l.google.com.300
MX30 aspmx2.googlemail.com.300
MX40 aspmx3.googlemail.com.300
TXT"google-site-verification=0W3EHt8wRzgBZUT4_w_NwM50y4aNtXUIa95yEkB7hbg"300
TXT"google-site-verification=gry2OoAsXMeGRyLmhhndx2c5TxFbvCqzUXR66_ZYMpc"300
TXT"v=spf1 include:_spf.google.com include:helpscoutemail.com include:servers.mcsv.net include:spf.mandrillapp.com include:zoho.com ip4:142.0.160.50/32 include:7320745.spf10.hubspotemail.net exists:%{i}._spf.mta.salesforce.com -all"300
CAA0 iodef "mailto:site-ops@teamtreehouse.com"300
CAA0 issue "amazon.com"300
CAA0 issue "amazonaws.com"300
CAA0 issue "amazontrust.com"300
CAA0 issue "awstrust.com"300
CAA0 issue "digicert.com"300
CAA0 issue "globalsign.com"300
CAA0 issue "letsencrypt.org"300
CAA0 issue "pki.goog"300
CAA0 issue "sectigo.com"300

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.
    #32
  • ✓ 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: amazon.com, amazonaws.com, amazontrust.com, awstrust.com, digicert.com, globalsign.com, letsencrypt.org, pki.goog, sectigo.com.