dbcourses.cn - robtex.com
dbcourses.cn
| DNSSEC | ⚠️ Not signed | ||||||
| A | 167.88.177.102🇨🇦 VMISS167.88.177.0/24 KURUN CLOUD INC | ||||||
| NS | ns1.exp.4cun.com ⚠️ Not in zone NS records | ||||||
| A | 60.190.243.160🇨🇳 CT-HangZhou-IDC60.190.243.0/24 Chinanet-HangZhou-IDC | ||||||
| NS | ns2.exp.4cun.com ⚠️ Not in zone NS records | ||||||
| A | 60.190.243.160🇨🇳 CT-HangZhou-IDC60.190.243.0/24 Chinanet-HangZhou-IDC | ||||||
| MX | mail.happyisp.com ⭐ | ||||||
| A | 5.161.49.68🇺🇸 HETZNER-CLOUD2-AS5.161.49.0/24 | ||||||
| PTR | mail.happyisp.com | ||||||
| A | 137.184.158.105🇺🇸 DIGITALOCEAN137.184.144.0/20 DigitalOcean | ||||||
| PTR | mail.happyisp.com | ||||||
| TXT | v=spf1 ip6:fd0d:d741:e183::/48 -all | ||||||
cn
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| NS | a.dns.cn ⭐ | ||||||
| NS | b.dns.cn | ||||||
| NS | c.dns.cn | ||||||
| NS | d.dns.cn | ||||||
| NS | e.dns.cn | ||||||
| NS | ns.cernet.net ⚠️ Not in parent delegation | ||||||
| SOA | a.dns.cnroot@cnnic.cn serial=2034674305 | ||||||
rank #21708 in the tld
Same first word
dbcourses.cn |
Similar names
DNS History
8 records (4 active, 4 former)
●NSns1.exp.4cun.com2026-04-15 → 2026-04-15 · 3 obs
● 2026-04-15 19:06:58
● 2026-04-15 19:07:00
○NSns1.judns.com2026-03-30 → 2026-03-30 · 3 obs
○ 2026-04-15 19:06:58
○ 2026-04-15 19:07:00
○NSns1.julydns.com2026-03-30 → 2026-03-30 · 3 obs
○ 2026-04-15 19:06:58
○ 2026-04-15 19:07:00
●NSns2.exp.4cun.com2026-04-15 → 2026-04-15 · 3 obs
● 2026-04-15 19:06:58
● 2026-04-15 19:07:00
○NSns2.judns.com2026-03-30 → 2026-03-30 · 3 obs
○ 2026-04-15 19:06:58
○ 2026-04-15 19:07:00
○NSns2.julydns.com2026-03-30 → 2026-03-30 · 3 obs
○ 2026-04-15 19:06:58
○ 2026-04-15 19:07:00
●MXmail.happyisp.com2026-04-15 → 2026-04-15 · 2 obs
● 2026-04-15 19:07:00
●A167.88.177.1022026-04-15 → 2026-04-15 · 2 obs
● 2026-04-15 19:07:00
🔍 DNS Trace
📋 Delegation Chain
| Zone | Nameservers | Glue |
|---|---|---|
| cn | a.dns.cn, b.dns.cn, c.dns.cn, d.dns.cn... | - |
| dbcourses.cn | ns1.exp.4cun.com, ns2.exp.4cun.com | - |
✅ Authoritative Response
Server:60.190.243.160
NS records: ns1.exp.4cun.com, ns2.exp.4cun.com
🔒 DNSSEC Status
⚠️ Insecure (no DNSSEC)
No DS record for dbcourses.cn (unsigned zone)
⏱️ Timing
Total: 1786ms | Queries: -
📄 Records
| Type | Count | Sample Data |
|---|---|---|
| A | 1 | 167.88.177.102 |
| MX | 1 | mail.happyisp.com (pri: 1) |
| TXT | 1 | v=spf1 ip6:fd0d:d741:e183::/48 -all |
Analysis
IP Addresses
dbcourses.cn resolves to one IP number: 167.88.177.102.
other host names including 71882.cn, thomas-int.com.cn, szlsie.cn, hao0537.com.h60.allhosts.cn and rdxp.cn share IP numbers with dbcourses.cn.
Name Servers
dbcourses.cn is delegated to two name servers ns1.exp.4cun.com and ns2.exp.4cun.com.
dbcourses.cn shares the same name server setup as other domains, for instance chenjianing.cn, aplink.com.cn, qqwlwyjy.com, sokxue.com and aviadoni.com.
dbcourses.cn at least partially shares name servers with other domains, for instance mhtimes.cn, mtoctdl.cn, jindehen.com and yxconnection.cn.
these name servers are often used together with ns3.exp.4cun.com, ns4.exp.4cun.com, ns5.exp.4cun.com and ns6.exp.4cun.com.
Host names with a single IP:
ns1.exp.4cun.com points to 60.190.243.160.
ns2.exp.4cun.com points to 60.190.243.160.
Host names pointing to 60.190.243.160: ns1.exp.4cun.com and ns2.exp.4cun.com.
Mail Servers
dbcourses.cn is handled by a single mail server, mail.happyisp.com.
dbcourses.cn shares the same mail server setup as other domains, for instance jingge.cn, yepi.cn, xxmr.com, 7119.cn and fout.cn.
mail.happyisp.com resolves to two IP numbers: 5.161.49.68 and 137.184.158.105.