🛡️Domain Reputation CheckBlocklist, phishing & malware status→

`problemsolving.courses`

DNSSEC	⚠️ Not signed
A	2606:4700:3036::6815:2516^{🇺🇸 Cloudflare2606:4700:3036::/48 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	2606:4700:3037::ac43:cb46^{🇺🇸 Cloudflare2606:4700:3037::/48 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	104.21.37.22^{Cloudflare104.21.32.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
A	172.67.203.70^{🇺🇸 Cloudflare172.67.192.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US} ✓ In HTTPS hints
NS	`randall.ns.cloudflare.com` ⭐
		A	2606:4700:58::a29f:2ceb^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`randall.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c3eb^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`randall.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:23eb^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`randall.ns.cloudflare.com`
		A	108.162.195.235^{🇺🇸 Cloudflare108.162.195.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`randall.ns.cloudflare.com`
		A	162.159.44.235^{Cloudflare162.159.32.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`randall.ns.cloudflare.com`
		A	172.64.35.235^{🇺🇸 Cloudflare172.64.35.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`randall.ns.cloudflare.com`
NS	`stella.ns.cloudflare.com`
		A	2606:4700:50::a29f:269a^{🇺🇸 Cloudflare2606:4700:50::/44 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`stella.ns.cloudflare.com`
		A	2803:f800:50::6ca2:c29a^{🇨🇷 Cloudflare2803:f800:50::/45 LACNIC generated route6 for CloudFlare Latin America S.R.L}
			PTR	`stella.ns.cloudflare.com`
		A	2a06:98c1:50::ac40:229a^{🇺🇸 Cloudflare2a06:98c1:50::/45}
			PTR	`stella.ns.cloudflare.com`
		A	108.162.194.154^{🇺🇸 Cloudflare108.162.194.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`stella.ns.cloudflare.com`
		A	162.159.38.154^{Cloudflare162.159.32.0/20 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`stella.ns.cloudflare.com`
		A	172.64.34.154^{🇺🇸 Cloudflare172.64.34.0/24 , Inc. 101 Townsend Street, San Francisco, California 94107, US}
			PTR	`stella.ns.cloudflare.com`
MX	`smtp.google.com` ⭐
		A	2607:f8b0:4004:c19::1a^{🇺🇸 Google2607:f8b0:4004::/48}
			PTR	`bk-in-f26.1e100.net`
		A	2607:f8b0:4004:c19::1b^{🇺🇸 Google2607:f8b0:4004::/48}
			PTR	`bk-in-f27.1e100.net`
		A	2607:f8b0:4004:c29::1a^{🇺🇸 Google2607:f8b0:4004::/48}
			PTR	`yuiadum-in-f26.1e100.net`
		A	2607:f8b0:4004:c29::1b^{🇺🇸 Google2607:f8b0:4004::/48}
			PTR	`yuiadum-in-f27.1e100.net`
		A	142.251.111.26^{🇺🇸 Google142.251.111.0/24}
			PTR	`bk-in-f26.1e100.net`
		A	142.251.111.27^{🇺🇸 Google142.251.111.0/24}
			PTR	`bk-in-f27.1e100.net`
		A	172.253.63.27^{🇺🇸 Google172.253.63.0/24}
			PTR	`bi-in-f27.1e100.net`
		A	173.194.45.26^{🇺🇸 Google173.194.0.0/16}
			PTR	`yuiadum-in-f26.1e100.net`
		A	173.194.45.27^{🇺🇸 Google173.194.0.0/16}
			PTR	`yuiadum-in-f27.1e100.net`
TXT	`google-site-verification=m_YNK8prM9zhAP2EQstq_mpxhGPytSIx1MZkLWl9VxY`
TXT	`v=spf1 include:_spf.google.com ~all`
HTTPS	HTTP/3, HTTP/2 ✓ hints match
		IPv4 hints	104.21.37.22, 172.67.203.70
		IPv6 hints	2606:4700:3036::6815:2516, 2606:4700:3037::ac43:cb46
		ECH	X25519, HKDF-SHA256 + AES-128-GCM draft, id=238, name=cloudflare-ech.com
SOA	`randall.ns.cloudflare.com`dns@cloudflare.com serial=2412558238

`courses`

	DNSSEC	🔒 Signed (DS record present)
	NS	`a.nic.courses` ⭐
	NS	`b.nic.courses`
	NS	`c.nic.courses`
	NS	`x.nic.courses`
	NS	`y.nic.courses`
	NS	`z.nic.courses`
	SOA	`a.nic.courses`admin@tldns.godaddy serial=1787392860

⚠️ On DNS blocklist: spam-tlds

Same first word

Previous names

Next names

DNS History

7 records (7 active, 0 former)

●NSrandall.ns.cloudflare.com2026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●NSstella.ns.cloudflare.com2026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●MXsmtp.google.com2026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●A104.21.37.222026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●A172.67.203.702026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●A2606:4700:3036::6815:25162026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

●A2606:4700:3037::ac43:cb462026-08-18 → 2026-08-22 · 2 obs

● 2026-08-18 02:06:50
● 2026-08-22 10:33:22

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
courses	c.nic.courses, x.nic.courses, a.nic.courses, z.nic.courses...	12 records
problemsolving.courses	stella.ns.cloudflare.com, randall.ns.cloudflare.com	-

✅ Authoritative Response

Server:172.64.34.154

NS records: stella.ns.cloudflare.com, randall.ns.cloudflare.com

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for problemsolving.courses (unsigned zone)

⏱️ Timing

Total: 1302ms | Queries: -

📄 Records

Type	Count	Sample Data
A	2	`172.67.203.70, 104.21.37.22`
AAAA	2	`2606:4700:3037::ac43:cb46, 2606:4700:3036::6815:2516`
NS	2	`randall.ns.cloudflare.com, stella.ns.cloudflare.com`
MX	1	`smtp.google.com (pri: 1)`
TXT	2	`google-site-verification=m_YNK8prM9zhAP2, v=spf1 include:_spf.google.com ~all`
HTTPS	1	`{"priority":1,"target":".","alpn":["h3",`
SOA	1	`randall.ns.cloudflare.com dns.cloudflare`

📌 Glue Records Collected

Total: 12

In-bailiwick: 12 (a.nic.courses, b.nic.courses, c.nic.courses...)

Analysis

IP Addresses

problemsolving.courses has four IP addresses: 104.21.37.22, 172.67.203.70, 2606:4700:3036::6815:2516 and 2606:4700:3037::ac43:cb46.

free5.gr, thedataroom.online, trumpetersociety.com and two other host names share IP numbers with problemsolving.courses.

Name Servers

DNS delegation for problemsolving.courses points to two name servers: randall.ns.cloudflare.com and stella.ns.cloudflare.com.

problemsolving.courses uses the same name servers as several other domains — among them spokenenglish.courses, englishgrammar.courses, kfgroupcoltd.com and two more.

problemsolving.courses shares at least some of its name servers with other domains, including mimim566k.shop, melhorcasino-online-portugal.com, panen143iyt.live and two others.

These name servers are frequently paired with the name servers rene.ns.cloudflare.com and lucy.ns.cloudflare.com.

Hostnames that resolve to 6 IP addresses:

randall.ns.cloudflare.com has IP addresses 108.162.195.235, 162.159.44.235 and 172.64.35.235, plus 3 other.

stella.ns.cloudflare.com has IP addresses 108.162.194.154, 162.159.38.154 and 172.64.34.154, plus 3 other.

Mail Servers

Mail for problemsolving.courses is handled by a single mail server, smtp.google.com.

problemsolving.courses uses an identical mail server configuration to several other domains — among them smarthousecolombia.com, tryreviewbuddy.ca, pdmmechanical.com and two more.

problemsolving.courses has mail servers in common with other domains — for example ligadata.com, politrans.md and marszniepodleglosci.pl.

This set of mail servers commonly appears together with the mail servers alt1.aspmx.l.google.com.

smtp.google.com resolves to 9 IP addresses — 142.251.111.26, 142.251.111.27, 172.253.63.27 and 6 others.

problemsolving.courses - robtex.com