`flexzen.app`

DNSSEC	⚠️ Not signed
A	103.221.223.163^{🇻🇳 AZDIGI-AS-VN103.221.220.0/22 AZDIGI-VN}
NS	`ns1.zonedns.vn` ⭐
		A	2401:c080:1400:1cd4:5400:5ff:fe80:ec33^{🇸🇬 AS-VULTR2401:c080:1400::/38 Vultr Assigned Prefix}
		A	64.176.84.220^{🇸🇬 AS-VULTR64.176.80.0/20 Vultr Assigned Prefix}
			PTR	`ns1.zonedns.vn`
NS	`ns2.zonedns.vn`
		A	2401:c080:1400:1cd4:5400:5ff:fe80:ec33^{🇸🇬 AS-VULTR2401:c080:1400::/38 Vultr Assigned Prefix}
		A	103.176.178.51^{🇻🇳 NHAN-HOA-AS-VN103.176.178.0/24 NINETECH-VN}
NS	`ns3.zonedns.vn`
		A	2001:df1:3200::15^{🇻🇳 NHAN-HOA-AS-VN2001:df1:3200::/48 NHANHOA-VN}
		A	103.28.36.30^{🇻🇳 NHAN-HOA-AS-VN103.28.36.0/22 NHANHOA-VN}
NS	`ns4.zonedns.vn` ⚠️ Not in zone NS records
		A	2001:df1:3200::15^{🇻🇳 NHAN-HOA-AS-VN2001:df1:3200::/48 NHANHOA-VN}
		A	103.28.39.159^{🇻🇳 NHAN-HOA-AS-VN103.28.36.0/22 NHANHOA-VN}
MX	`smtp.flexzen.app` ⭐
		A	171.244.143.43^{🇻🇳 VTDC-AS-VN171.244.140.0/22 Proxy-registered route object}
SOA	`ns1.zonedns.vn`root@flexzen.app 2026-04-08 #3

`app`

	DNSSEC	🔒 Signed (DS record present)
	NS	`ns-tld1.charlestonroadregistry.com` ⭐
	NS	`ns-tld2.charlestonroadregistry.com`
	NS	`ns-tld3.charlestonroadregistry.com`
	NS	`ns-tld4.charlestonroadregistry.com`
	NS	`ns-tld5.charlestonroadregistry.com`
	SOA	`ns-tld1.charlestonroadregistry.com`cloud-dns-hostmaster@google.com serial=101427

🔒 HSTS Preload (+subdomains)

Subdomains

smtp.flexzen.app

Same first word

flexzen.app

flexzen.com

Similar names

zenflex.de

zenflex.my

zenflex.eu

zenflex.com

zenflex.site

DNS History

6 records (6 active, 0 former)

●NSns1.zonedns.vn2026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

●NSns2.zonedns.vn2026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

●NSns3.zonedns.vn2026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

●NSns4.zonedns.vn2026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

●MXsmtp.flexzen.app2026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

●A103.221.223.1632026-05-01 → 2026-05-08 · 2 obs

● 2026-05-01 09:02:08
● 2026-05-08 22:11:20

🔍 DNS Trace

📋 Delegation Chain

Zone	Nameservers	Glue
app	ns-tld2.charlestonroadregistry.com, ns-tld4.charlestonroadregistry.com, ns-tld3.charlestonroadregistry.com, ns-tld1.charlestonroadregistry.com...	-
flexzen.app	ns2.zonedns.vn, ns3.zonedns.vn, ns1.zonedns.vn, ns4.zonedns.vn	-

✅ Authoritative Response

Server:103.28.39.159

NS records: ns2.zonedns.vn, ns3.zonedns.vn, ns1.zonedns.vn, ns4.zonedns.vn

🔒 DNSSEC Status

⚠️ Insecure (no DNSSEC)

No DS record for flexzen.app (unsigned zone)

⏱️ Timing

Total: 1935ms | Queries: -

📄 Records

Type	Count	Sample Data
A	1	`103.221.223.163`
NS	3	`ns3.zonedns.vn, ns1.zonedns.vn...`
MX	1	`smtp.flexzen.app (pri: 20)`
SOA	1	`ns1.zonedns.vn root.flexzen.app`

Analysis

Hierarchy

The parent of smtp.flexzen.app is flexzen.app.

IP Addresses

flexzen.app points to a single IP address: 103.221.223.163.

Other host names such as zenone.app, orapark.com, www.vietthien.com and vietthien.com share IP numbers with flexzen.app.

Name Servers

flexzen.app is delegated to four name servers: ns1.zonedns.vn, ns2.zonedns.vn, ns3.zonedns.vn and ns4.zonedns.vn.

flexzen.app at least partially shares name servers with other domains, for example t2t.com.vn, anhem.com.vn, tmsport.vn, ezstore.com.vn and cybersecurity.vn.