skycn.com

Checked 22 October 2026, 10:44 UTC · via 8.8.8.8
✗Problems found
21 passed 4 warnings 1 failed 5 info

Registration

info

.com generic · Internet Domain Name System Beijing Engineering Research Center LLC (ZDNS) · expires 2026-12-16

Found

TLD
.com (generic)
ICANN policies apply
yes
Registrar
Internet Domain Name System Beijing Engineering Research Center LLC (ZDNS)
Registered
16 December 1999
Last changed
12 September 2025
Expires
16 December 2026
Status
client delete prohibited, client transfer prohibited
Registry nameservers
ns1.skycn.com, ns2.skycn.com, ns3.skycn.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 2026-12-16 #3
    The registration is valid until 2026-12-16 (54 days).
  • ✓ Transfer locked #4
    Registry status: client delete prohibited, client transfer prohibited.
  • ✓ Registry and delegation match #5
    The nameservers registered at the registry are the ones published in DNS.

Delegation

warn

ns1.skycn.com, ns2.skycn.com, ns3.skycn.com

Found

Parent zone
com
Delegation from
a.gtld-servers.net (192.5.6.30)
NS at the parent
ns1.skycn.com, ns2.skycn.com, ns3.skycn.com
NS in the zone
ns1.skycn.com, ns2.skycn.com, ns3.skycn.com
NameserverAddressesNetwork (AS)Glue
ns1.skycn.com123.125.112.254AS4808 CHINA169-BJ - China Unicom Beijing Province Network, CN110.242.68.134
ns2.skycn.com220.181.33.31AS23724 CHINANET-IDC-BJ-AP - IDC, China Telecommunications Corporation, CN220.181.33.31
ns3.skycn.com153.3.238.93AS4837 CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN153.3.238.93

Checks

  • ✓ 3 nameservers #6
    Delegated to ns1.skycn.com, ns2.skycn.com, ns3.skycn.com.
  • ✓ Parent and zone agree #7
    The parent delegation and the zone's NS records list the same nameservers.
  • !
    Glue differs from the zone
    The addresses at the parent (glue) differ from the addresses in the zone: ns1.skycn.com (glue 110.242.68.134, zone 123.125.112.254). Update the glue at your registrar.
    #8
  • ✓ 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 3 IPv4 /24s and 0 IPv6 /48s.
  • ✓ 3 autonomous systems #11
    The nameservers are spread over: AS23724 (CHINANET-IDC-BJ-AP - IDC, China Telecommunications Corporation, CN): 1 address; AS4808 (CHINA169-BJ - China Unicom Beijing Province Network, CN): 1 address; AS4837 (CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN): 1 address.
  • 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
  • !
    No IPv6
    None of the nameservers has an IPv6 address, so IPv6-only resolvers can't reach them.
    #13

Nameservers

fail

2 of 3 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.skycn.com 123.125.112.254no responsenono / no--
ns2.skycn.com 220.181.33.31NOERROR, 146 ms, authoritativenoyes / yesrefusedbaidu dns
ns3.skycn.com 153.3.238.93NOERROR, 160 ms, authoritativenoyes / yesrefusedbaidu dns

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns1.skycn.com (123.125.112.254): read udp 46.225.38.91:57650->123.125.112.254:53: read: connection refused.
    #14
  • ✓ All authoritative #15
    Every responding nameserver answers authoritatively for the zone.
  • ✓ No recursion #16
    The nameservers do not answer recursive queries for other domains.
  • i
    Identifying string disclosed
    These nameservers answer version queries with a string that is not a version number: ns2.skycn.com: "baidu dns"; ns3.skycn.com: "baidu dns".
    #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 2012041463 · primary skycn.com

Found

Primary (MNAME)
skycn.com
Contact (RNAME)
sa.skycn.com
Serial
2012041463
Refresh / retry
300 s / 600 s
Expire
3600000 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
ns2.skycn.com (220.181.33.31)2012041463
ns3.skycn.com (153.3.238.93)2012041463

Checks

  • ✓ Serial 2012041463 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    refresh 5m is outside 20m–1d; retry 10m should be shorter than refresh 5m. Current values: refresh 5m, retry 10m, expire 1000h, negative TTL 10m.
    #23
  • i
    Hidden master
    The primary nameserver skycn.com is not listed as a nameserver: a hidden master that only feeds the public secondaries. That is a common setup; make sure it is not reachable for zone transfers from outside.
    #24
  • ✓ Contact sa@skycn.com #25
    The SOA RNAME sa.skycn.com means sa@skycn.com.
  • ✓ Date-based serial #26
    The serial 2012041463 follows the YYYYMMDDnn convention (2012-04-14).

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

6 records at the apex

Found

Read from
220.181.33.31:53
TypeValueTTL
NSns3.skycn.com.600
NSns2.skycn.com.600
NSns1.skycn.com.600
A110.242.69.67600
TXT"cpls0m70ghv010n0tcfj3y6421l4syqh"600
TXT"_1ma5p9ef2y4lf35xur1q0p8asu4z3xo"600

Checks

  • ✓ TTLs within range #32
    TTLs: A 10m, NS 10m. The NS TTL at the parent is 2d and in the zone 10m; 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