21tb.com - robtex.com
21tb.com
| DNSSEC | ⚠️ Not signed | ||||||
| A | 123.103.18.6🇨🇳 CHINA169-BJ123.103.16.0/22 China Telecom Beijing Co. Ltd. | ||||||
| PTR | 123.103.18.6-bj-cnc | ||||||
| NS | ns1.21tb.com ⭐ | ||||||
| A | 101.132.254.136🇨🇳 Alibaba-Cloud101.132.0.0/16 Alibaba (US) Technology Co., Ltd. | ||||||
| NS | ns2.21tb.com | ||||||
| A | 120.26.181.11🇨🇳 Alibaba-Cloud120.26.0.0/16 | ||||||
| NS | ns3.21tb.com | ||||||
| A | 47.84.45.240🇺🇸 Alibaba-Cloud47.84.0.0/17 Proxy-registered route object | ||||||
| MX | mx-antispam.21tb.com ⭐ | ||||||
| A | 122.14.197.5🇨🇳 CHINAMOBILE-CN122.14.192.0/20 | ||||||
| PTR | mailcheck.21tb.com | ||||||
| TXT | v=spf1 ip4:122.14.197.5 -all | ||||||
| SOA | ns1.21tb.comhezitong@21tb.com serial=2021043313 | ||||||
com
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| NS | a.gtld-servers.net ⭐ | ||||||
| NS | b.gtld-servers.net | ||||||
| NS | c.gtld-servers.net | ||||||
| NS | d.gtld-servers.net | ||||||
| NS | e.gtld-servers.net | ||||||
| NS | f.gtld-servers.net | ||||||
| NS | g.gtld-servers.net | ||||||
| NS | h.gtld-servers.net | ||||||
| NS | i.gtld-servers.net | ||||||
| NS | j.gtld-servers.net | ||||||
| NS | k.gtld-servers.net | ||||||
| NS | l.gtld-servers.net | ||||||
| NS | m.gtld-servers.net | ||||||
| SOA | a.gtld-servers.netnstld@verisign-grs.com serial=1771291435 | ||||||
rank #155121 in the tld
📈 Tranco rank: #326,054
Subdomains
goertek-elearning.21tb.com |
mx1.21tb.com |
21tb-file4.21tb.com |
ns2.21tb.com |
fjnx.21tb.com |
sxjtzx.21tb.com |
ns1.21tb.com |
ns3.21tb.com |
gdrc.21tb.com |
arup.21tb.com |
mailcheck.21tb.com |
mail.21tb.com |
mx-antispam.21tb.com |
mx2.21tb.com |
Same first word
Similar names
12tb.com |
t1b2.com |
1t2b.cn |
21bt.net |
bt12.de |
tb21.com |
12bt.biz |
12bt.cn |
bt21.com |
b1t2.net |
b1t2.pages.dev |
12bt.net |
bt21.nl |
bt21.jp |
bt12.cc |
bt21.co.za |
DNS History
10 records (5 active, 5 former)
○NS21tb-ns1.cneln.net2015-06-21 → 2017-02-20 · 4 obs
● 2017-02-20 04:16:08
○ 2026-02-15 16:43:34
○ 2026-03-15 02:57:50
●NSns1.21tb.com2026-02-15 → 2026-03-15 · 3 obs
● 2026-02-15 16:43:34
● 2026-03-15 02:57:50
●NSns2.21tb.com2026-02-15 → 2026-03-15 · 3 obs
● 2026-02-15 16:43:34
● 2026-03-15 02:57:50
●NSns3.21tb.com2026-02-15 → 2026-03-15 · 3 obs
● 2026-02-15 16:43:34
● 2026-03-15 02:57:50
●MXmx-antispam.21tb.com2026-02-15 → 2026-03-15 · 3 obs
● 2026-02-15 16:43:34
● 2026-03-15 02:57:50
○MXmx1.21tb.com2015-06-21 → 2017-02-20 · 4 obs
● 2017-02-20 04:16:08
○ 2026-02-15 16:43:34
○ 2026-03-15 02:57:50
○MXmx2.21tb.com2015-06-21 → 2017-02-20 · 4 obs
● 2017-02-20 04:16:08
○ 2026-02-15 16:43:34
○ 2026-03-15 02:57:50
○A120.132.46.442016-11-26 → 2017-02-20 · 5 obs
● 2016-11-26 21:22:42
● 2017-02-20 04:16:08
○ 2026-02-15 16:43:34
○ 2026-03-15 02:57:50
●A123.103.18.62026-02-15 → 2026-03-15 · 3 obs
● 2026-02-15 16:43:34
● 2026-03-15 02:57:50
○A123.103.18.82015-06-21 → 2016-03-31 · 4 obs
● 2016-03-31 23:57:14
○ 2016-11-26 21:22:42
○ 2026-03-15 02:57:50
🔍 DNS Trace
📋 Delegation Chain
| Zone | Nameservers | Glue |
|---|---|---|
| com | b.gtld-servers.net, h.gtld-servers.net, d.gtld-servers.net, a.gtld-servers.net... | - |
| 21tb.com | ns1.21tb.com, ns2.21tb.com, ns3.21tb.com | 3 records |
✅ Authoritative Response
Server: 47.84.45.240
NS records: ns1.21tb.com, ns2.21tb.com, ns3.21tb.com
🔒 DNSSEC Status
⚠️ Insecure (no DNSSEC)
No DS record for 21tb.com (unsigned zone)
⏱️ Timing
Total: 2714ms | Queries: -
📄 Records
| Type | Count | Sample Data |
|---|---|---|
| A | 1 | 123.103.18.6 |
| NS | 3 | ns1.21tb.com, ns2.21tb.com... |
| MX | 1 | mx-antispam.21tb.com (pri: 10) |
| TXT | 1 | v=spf1 ip4:122.14.197.5 -all |
| SOA | 1 | ns1.21tb.com hezitong.21tb.com |
📌 Glue Records Collected
Total: 3
In-bailiwick: 3 (ns1.21tb.com, ns2.21tb.com, ns3.21tb.com)
Analysis
Hierarchy
21tb.com is the parent of goertek-elearning.21tb.com, mx1.21tb.com, 21tb-file4.21tb.com, ns2.21tb.com, fjnx.21tb.com and several other host names.
IP Addresses
21tb.com points to a single IP: 123.103.18.6.
Other host names such as arup.21tb.com, mx2.21tb.com, 21tb.cn and www.cneln.com share IP numbers with 21tb.com.
Name Servers
21tb.com is delegated to three name servers: ns1.21tb.com, ns2.21tb.com and ns3.21tb.com.
21tb.com shares name servers with other domains to some extent, for instance 21tbc.com, eln.com.cn, cneln.com and cneln.net.
Host names with one IP number:
ns1.21tb.com points to: 101.132.254.136.
ns2.21tb.com points to: 120.26.181.11.
ns3.21tb.com points to: 47.84.45.240.
Mail Servers
21tb.com is served by a single mail server, mx-antispam.21tb.com.
21tb.com shares the same mail server setup as other domains, such as 21tbc.com and eln.com.cn.
mx-antispam.21tb.com points to IP number 122.14.197.5.