`51testbook.com`

DNSSEC	⚠️ Not signed
A	2606:4700:3031::ac43:cd78^{🇺🇸 Cloudflare2606:4700:3031::/48 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	2606:4700:3036::6815:34f0^{🇺🇸 Cloudflare2606:4700:3036::/48 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.21.52.240^{Cloudflare104.21.48.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	172.67.205.120^{🇺🇸 Cloudflare172.67.192.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
NS	`aspen.ns.cloudflare.com` ⭐
		A	2606:4700:50::a29f:266d^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`aspen.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c26d^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`aspen.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:226d^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`aspen.ns.cloudflare.com`
		A	108.162.194.109^{🇺🇸 Cloudflare108.162.194.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`aspen.ns.cloudflare.com`
		A	162.159.38.109^{Cloudflare162.159.32.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`aspen.ns.cloudflare.com`
		A	172.64.34.109^{🇺🇸 Cloudflare172.64.34.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`aspen.ns.cloudflare.com`
NS	`nash.ns.cloudflare.com`
		A	2606:4700:58::adf5:3bd1^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`nash.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c1d1^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`nash.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:21d1^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`nash.ns.cloudflare.com`
		A	108.162.193.209^{🇺🇸 Cloudflare108.162.193.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`nash.ns.cloudflare.com`
		A	172.64.33.209^{🇺🇸 Cloudflare172.64.33.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`nash.ns.cloudflare.com`
		A	173.245.59.209^{🇺🇸 Cloudflare173.245.59.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`nash.ns.cloudflare.com`
HTTPS	HTTP/3, HTTP/2 ✓ hints match
		IPv4 hints	104.21.52.240, 172.67.205.120
		IPv6 hints	2606:4700:3031::ac43:cd78, 2606:4700:3036::6815:34f0
		ECH	X25519, HKDF-SHA256 + AES-128-GCM draft, id=125, name=cloudflare-ech.com
SOA	`aspen.ns.cloudflare.com`dns@cloudflare.com serial=2408382495

`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.net`nstld@verisign-grs.com serial=1785530142

Same first word

51testbook.com

DNS History

15 records (6 active, 9 former)

●NSaspen.ns.cloudflare.com2026-04-14 → 2026-07-31 · 3 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-07-31 20:42:08

○NSdns7.hichina.com2015-08-14 → 2018-01-31 · 4 obs

● 2015-08-14 22:52:22
● 2018-01-31 14:32:18
○ 2026-04-14 02:22:58
○ 2026-07-31 20:42:08

○NSdns8.hichina.com2015-08-14 → 2018-01-31 · 4 obs

● 2015-08-14 22:52:22
● 2018-01-31 14:32:18
○ 2026-04-14 02:22:58
○ 2026-07-31 20:42:08

●NSnash.ns.cloudflare.com2026-04-14 → 2026-07-31 · 3 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-07-31 20:42:08

●A104.21.52.2402026-04-14 → 2026-07-31 · 6 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-05-11 22:24:52
○ 2026-05-18 12:32:38
● 2026-06-14 08:08:30
● 2026-07-31 20:42:08

○A123.57.6.62015-08-14 → 2018-01-31 · 4 obs

● 2015-08-14 22:52:22
● 2018-01-31 14:32:18
○ 2026-04-14 02:22:58
○ 2026-07-31 20:42:08

●A172.67.205.1202026-04-14 → 2026-07-31 · 6 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-05-11 22:24:52
○ 2026-05-18 12:32:38
● 2026-06-14 08:08:30
● 2026-07-31 20:42:08

○A188.114.96.02026-05-18 → 2026-05-18 · 4 obs

○ 2026-05-11 22:24:52
● 2026-05-18 12:32:38
○ 2026-06-14 08:08:30
○ 2026-07-31 20:42:08

○A188.114.97.02026-05-18 → 2026-05-18 · 4 obs

○ 2026-05-11 22:24:52
● 2026-05-18 12:32:38
○ 2026-06-14 08:08:30
○ 2026-07-31 20:42:08

●A2606:4700:3031::ac43:cd782026-07-31 → 2026-07-31 · 3 obs

○ 2026-06-14 08:08:30
● 2026-07-31 20:42:06
● 2026-07-31 20:42:08

○A2606:4700:3035::6815:34f02026-04-14 → 2026-06-14 · 7 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-05-11 22:24:52
○ 2026-05-18 12:32:38
● 2026-06-14 08:08:30
○ 2026-07-31 20:42:06
○ 2026-07-31 20:42:08

●A2606:4700:3036::6815:34f02026-07-31 → 2026-07-31 · 3 obs

○ 2026-06-14 08:08:30
● 2026-07-31 20:42:06
● 2026-07-31 20:42:08

○A2606:4700:3036::ac43:cd782026-04-14 → 2026-06-14 · 7 obs

○ 2018-01-31 14:32:18
● 2026-04-14 02:22:58
● 2026-05-11 22:24:52
○ 2026-05-18 12:32:38
● 2026-06-14 08:08:30
○ 2026-07-31 20:42:06
○ 2026-07-31 20:42:08

○A2a06:98c1:3120::2026-05-18 → 2026-05-18 · 4 obs

○ 2026-05-11 22:24:52
● 2026-05-18 12:32:38
○ 2026-06-14 08:08:30
○ 2026-07-31 20:42:08

○A2a06:98c1:3121::2026-05-18 → 2026-05-18 · 4 obs

○ 2026-05-11 22:24:52
● 2026-05-18 12:32:38
○ 2026-06-14 08:08:30
○ 2026-07-31 20:42:08

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
com	d.gtld-servers.net, h.gtld-servers.net, k.gtld-servers.net, j.gtld-servers.net...	-
51testbook.com	nash.ns.cloudflare.com, aspen.ns.cloudflare.com	12 records

✅ Authoritative Response

Server:108.162.193.209

NS records: nash.ns.cloudflare.com, aspen.ns.cloudflare.com

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for 51testbook.com (unsigned zone)

⏱️ Timing

Total: 1543ms | Queries: -

📄 Records

Type	Count	Sample Data
A	2	`104.21.52.240, 172.67.205.120`
AAAA	2	`2606:4700:3036::6815:34f0, 2606:4700:3031::ac43:cd78`
NS	2	`aspen.ns.cloudflare.com, nash.ns.cloudflare.com`
HTTPS	1	`{"priority":1,"target":".","alpn":["h3",`
SOA	1	`aspen.ns.cloudflare.com dns.cloudflare.c`

📌 Glue Records Collected

Total: 12

Out-of-bailiwick: 12 (nash.ns.cloudflare.com, nash.ns.cloudflare.com, nash.ns.cloudflare.com...)

Analysis

IP Addresses

51testbook.com resolves to four IP addresses: 104.21.52.240, 172.67.205.120, 2606:4700:3031::ac43:cd78 and 2606:4700:3036::6815:34f0.

mody.dk, architectsde.com, 56e3dee053b7.mp3nota.info plus two other host names have IP numbers in common with 51testbook.com.

Name Servers

51testbook.com has two authoritative name servers — aspen.ns.cloudflare.com and nash.ns.cloudflare.com.

The name server configuration of 51testbook.com is shared with other domains, for instance bbjade.com, whzxlife.com, xjgstx.com and two others.

51testbook.com has at least partial name server overlap with other domains, such as zuxiechina.com, polycarbonatbg.com, pre-registration98529.info and two others.

These name servers tend to appear together with the name servers gordon.ns.cloudflare.com, meiling.ns.cloudflare.com and donna.ns.cloudflare.com.

Hosts with 6 IP addresses each:

aspen.ns.cloudflare.com points to 108.162.194.109, 162.159.38.109, 172.64.34.109 and 3 other IP addresses.

nash.ns.cloudflare.com points to 108.162.193.209, 172.64.33.209, 173.245.59.209 and 3 other IP addresses.

51testbook.com - robtex.com

51testbook.com

com

Same first word

DNS History

🔍 DNS Trace

📋 Delegation Chain

✅ Authoritative Response

🔒 DNSSEC Status

⏱️ Timing

📄 Records

📌 Glue Records Collected

Analysis

IP Addresses

Name Servers

`51testbook.com`

`com`