nchem.com

Checked 22 October 2026, 10:01 UTC · via 8.8.8.8
✗Problems found
16 passed 5 warnings 2 failed 8 info

Registration

info

.com generic · Bizcn.com, Inc. · expires 2028-10-10

Found

TLD
.com (generic)
ICANN policies apply
yes
Registrar
Bizcn.com, Inc.
Registered
10 October 2004
Last changed
18 September 2026
Expires
10 October 2028
Status
client transfer prohibited
Registry nameservers
ns13.dns.com.cn, ns14.dns.com.cn
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 2028-10-10 #3
    The registration is valid until 2028-10-10 (718 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

warn

ns13.dns.com.cn, ns14.dns.com.cn

Found

Parent zone
com
Delegation from
a.gtld-servers.net (192.5.6.30)
NS at the parent
ns13.dns.com.cn, ns14.dns.com.cn
NS in the zone
ns1.dns.com.cn, ns2.dns.com.cn
NameserverAddressesNetwork (AS)Glue
ns1.dns.com.cn (zone only)61.172.183.70 61.240.129.114 240c:4082:ffff:ff01:0:d:0:34aAS4811 CHINANET-SHANGHAI-MAN - China Telecom (Group), CN AS4837 CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN AS38365 Baidu - Beijing Baidu Netcom Science and Technology Co., Ltd., CN-
ns13.dns.com.cn (parent only)61.172.183.76AS4811 CHINANET-SHANGHAI-MAN - China Telecom (Group), CN-
ns14.dns.com.cn (parent only)61.240.129.114AS4837 CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN-
ns2.dns.com.cn (zone only)61.172.183.76 61.240.129.147 240c:4082:ffff:ff01:0:d:0:69AS4811 CHINANET-SHANGHAI-MAN - China Telecom (Group), CN AS4837 CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN AS38365 Baidu - Beijing Baidu Netcom Science and Technology Co., Ltd., CN-

Checks

  • i
    2 nameservers
    Two nameservers meet the minimum; RFC 2182 recommends three or more for important zones: ns13.dns.com.cn, ns14.dns.com.cn.
    #6
  • !
    NS sets differ
    The nameservers at the parent and in the zone should be the same. Only at the parent: ns13.dns.com.cn, ns14.dns.com.cn; only in the zone: ns1.dns.com.cn, ns2.dns.com.cn. ns1.dns.com.cn, ns13.dns.com.cn, ns14.dns.com.cn, ns2.dns.com.cn report NS ns1.dns.com.cn ns2.dns.com.cn.
    #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.
  • i
    One address family in one network
    all IPv6 addresses are in 240c:4082:ffff::/48, while the other address family is spread over several networks.
    #10
  • ✓ 3 autonomous systems #11
    The nameservers are spread over: AS38365 (Baidu - Beijing Baidu Netcom Science and Technology Co., Ltd., CN): 2 addresses; AS4811 (CHINANET-SHANGHAI-MAN - China Telecom (Group), CN): 3 addresses; AS4837 (CHINA169-Backbone - CHINA UNICOM China169 Backbone, CN): 3 addresses.
  • i
    All nameserver names under .cn
    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
  • i
    Partly IPv6
    These nameservers have no IPv6 address: ns13.dns.com.cn, ns14.dns.com.cn.
    #13

Nameservers

fail

6 of 8 addresses answer authoritatively

Found

NameserverAnswerRecursionTCP / EDNSAXFRVersion
ns1.dns.com.cn 61.172.183.70NOERROR, 371 ms, authoritativenono / norefused9.11.0pre-alpha
ns1.dns.com.cn 61.240.129.114NOERROR, 157 ms, authoritativenono / yesrefused9.11.0pre-alpha
ns1.dns.com.cn 240c:4082:ffff:ff01:0:d:0:34ano responsenono / no--
ns13.dns.com.cn 61.172.183.76NOERROR, 199 ms, authoritativenono / norefused9.11.0pre-alpha
ns14.dns.com.cn 61.240.129.114NOERROR, 182 ms, authoritativenono / yesrefused9.11.0pre-alpha
ns2.dns.com.cn 61.172.183.76NOERROR, 210 ms, authoritativenono / norefused9.11.0pre-alpha
ns2.dns.com.cn 61.240.129.147NOERROR, 453 ms, authoritativenono / yesrefused9.11.0pre-alpha
ns2.dns.com.cn 240c:4082:ffff:ff01:0:d:0:69no responsenono / no--

Checks

  • ✗
    Nameservers not responding
    These addresses did not answer, so resolvers waste time on timeouts: ns1.dns.com.cn (240c:4082:ffff:ff01:0:d:0:34a): read udp [2a01:4f8:1c1c:eebf::1]:34085->[240c:4082:ffff:ff01:0:d:0:34a]:53: i/o timeout; ns2.dns.com.cn (240c:4082:ffff:ff01:0:d:0:69): read udp [2a01:4f8:1c1c:eebf::1]:53424->[240c:4082:ffff:ff01:0:d:0:69]:53: i/o timeout.
    #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.
  • !
    Software version disclosed
    These nameservers report their software version via version.bind/version.server, which helps attackers find known vulnerabilities: ns1.dns.com.cn: "9.11.0pre-alpha"; ns13.dns.com.cn: "9.11.0pre-alpha"; ns14.dns.com.cn: "9.11.0pre-alpha"; ns2.dns.com.cn: "9.11.0pre-alpha". 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: ns1.dns.com.cn (61.172.183.70): dial tcp 61.172.183.70:53: i/o timeout; ns1.dns.com.cn (61.240.129.114): dial tcp 61.240.129.114:53: i/o timeout; ns13.dns.com.cn (61.172.183.76): dial tcp 61.172.183.76:53: i/o timeout; ns14.dns.com.cn (61.240.129.114): dial tcp 61.240.129.114:53: i/o timeout; ns2.dns.com.cn (61.172.183.76): dial tcp 61.172.183.76:53: i/o timeout; ns2.dns.com.cn (61.240.129.147): dial tcp 61.240.129.147:53: i/o timeout.
    #19
  • !
    No EDNS
    These nameservers don't support EDNS(0), needed for DNSSEC and answers larger than 512 bytes: ns1.dns.com.cn (61.172.183.70), ns13.dns.com.cn (61.172.183.76), ns2.dns.com.cn (61.172.183.76).
    #20
  • ✓ Public addresses #21
    All nameserver addresses are publicly routable.

SOA

warn

serial 12 · primary dns.bizcn.com

Found

Primary (MNAME)
dns.bizcn.com
Contact (RNAME)
abuse.bizcn.com
Serial
12
Refresh / retry
28800 s / 14400 s
Expire
14400 s
Negative TTL
600 s

Serial per nameserver

NameserverSerial
ns1.dns.com.cn (61.172.183.70)12
ns1.dns.com.cn (61.240.129.114)12
ns13.dns.com.cn (61.172.183.76)12
ns14.dns.com.cn (61.240.129.114)12
ns2.dns.com.cn (61.172.183.76)12
ns2.dns.com.cn (61.240.129.147)12

Checks

  • ✓ Serial 12 everywhere #22
    All nameservers serve the same version of the zone.
  • !
    Unusual SOA timers
    expire 4h is shorter than 7d; secondaries stop answering too soon when the primary is down; expire 4h must be longer than refresh + retry. Current values: refresh 8h, retry 4h, expire 4h, negative TTL 10m.
    #23
  • i
    Hidden master
    The primary nameserver dns.bizcn.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 abuse@bizcn.com #25
    The SOA RNAME abuse.bizcn.com means abuse@bizcn.com.
  • ✓ Counter serial #26
    The serial 12 is a plain counter.

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

5 records at the apex

Found

Read from
61.172.183.70:53
TypeValueTTL
SOAdns.bizcn.com. abuse.bizcn.com. 12 28800 14400 14400 600600
NSns2.dns.com.cn.600
NSns1.dns.com.cn.600
A42.96.138.2423600
MX10 mx11.dns.com.cn.3600

Checks

  • ✓ TTLs within range #32
    TTLs: A 1h, MX 1h, 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.
  • i
    Wildcard record
    A random name under the zone resolves, so there is a wildcard (*) record. Typos and non-existent hosts resolve too, which can confuse mail and certificate checks.
    #34
  • 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