server4u.cz - robtex.com
server4u.cz
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| A | 81.91.86.27🇨🇿 WEB4U81.91.80.0/21 | ||||||
| PTR | www.spravadomen.cz | ||||||
| NS | ns2.web4u.cz ⭐ | ||||||
| A | 2a02:a40:100:28ff::12🇨🇿 BlueTone-AS2a02:a40::/32 Ceske Radiokomunikace, a.s. | ||||||
| PTR | ns2.web4u.cz | ||||||
| A | 85.207.53.12🇨🇿 BlueTone-AS85.207.0.0/16 BlueTone-CRa-CZ Fourth address block | ||||||
| PTR | ns2.web4u.cz | ||||||
| NS | ns.web4u.cz | ||||||
| A | 2001:1568:fd::241🇨🇿 WEB4U2001:1568::/33 | ||||||
| PTR | ns.web4u.cz | ||||||
| A | 185.14.224.241🇨🇿 WEB4U185.14.224.0/23 | ||||||
| PTR | ns.web4u.cz | ||||||
| MX | mx1.mailchannels.net ⭐ 🔒 | ||||||
| A | 18.236.29.166🇺🇸 Amazon18.236.0.0/15 EC2 PDX prefix | ||||||
| PTR | ec2-18-236-29-166.us-west-2.compute.amazonaws.com | ||||||
| MX | mx2.mailchannels.net ⭐ 🔒 | ||||||
| A | 52.38.143.159🇺🇸 Amazon52.36.0.0/14 EC2 PDX prefix | ||||||
| PTR | ec2-52-38-143-159.us-west-2.compute.amazonaws.com | ||||||
| SOA | ns.web4u.czadmin@web4u.cz 2026-03-20 #0 | ||||||
cz
| DNSSEC | 🔒 Signed (DS record present) | ||||||
| NS | a.ns.nic.cz ⭐ 🔒 | ||||||
| NS | b.ns.nic.cz 🔒 | ||||||
| NS | c.ns.nic.cz 🔒 | ||||||
| NS | d.ns.nic.cz 🔒 | ||||||
| SOA | a.ns.nic.czhostmaster@nic.cz serial=1771291036 | ||||||
Subdomains
vs397.server4u.cz |
vs1269.server4u.cz |
vs205.server4u.cz |
m215.server4u.cz |
m216-1.server4u.cz |
m185.server4u.cz |
vs467.server4u.cz |
d313.server4u.cz |
vs424.server4u.cz |
m103.server4u.cz |
m253-2.server4u.cz |
vs199.server4u.cz |
vs170.server4u.cz |
vs449.server4u.cz |
vstest118.server4u.cz |
vs208.server4u.cz |
vs816.server4u.cz |
vs1283.server4u.cz |
vs1180.server4u.cz |
vs297.server4u.cz |
vs341.server4u.cz |
vs413.server4u.cz |
webmedia-mail.server4u.cz |
vs1129.server4u.cz |
vs233.server4u.cz |
vs472.server4u.cz |
vs416.server4u.cz |
d321.server4u.cz |
vs1010.server4u.cz |
d150.server4u.cz |
x10.server4u.cz |
vs318.server4u.cz |
m157.server4u.cz |
vw370.server4u.cz |
vsmycat1.server4u.cz |
m108-2.server4u.cz |
vs835.server4u.cz |
vs1244.server4u.cz |
m238.server4u.cz |
vs666.server4u.cz |
x20.server4u.cz |
vs478.server4u.cz |
vs448.server4u.cz |
vs821-2.server4u.cz |
vs440.server4u.cz |
zfs.server4u.cz |
vs332.server4u.cz |
vs1043.server4u.cz |
x36.server4u.cz |
ipmi-d301.server4u.cz |
d148.server4u.cz |
vs1207.server4u.cz |
m114.server4u.cz |
mbullseye.server4u.cz |
vs374.server4u.cz |
vs872.server4u.cz |
vs1292.server4u.cz |
vsmycat2.server4u.cz |
vsdan.server4u.cz |
d142.server4u.cz |
d341.server4u.cz |
z200.server4u.cz |
d334.server4u.cz |
vs148.server4u.cz |
vs450.server4u.cz |
vstest104.server4u.cz |
vs106.server4u.cz |
cybers-mailer.server4u.cz |
vstest110.server4u.cz |
vw408-ap.server4u.cz |
m212.server4u.cz |
vs345.server4u.cz |
m268.server4u.cz |
d104-4.server4u.cz |
vsmanaged.server4u.cz |
d327.server4u.cz |
vs163.server4u.cz |
vs339.server4u.cz |
d130.server4u.cz |
mimiaukro.server4u.cz |
vs843.server4u.cz |
vw369.server4u.cz |
d132.server4u.cz |
vs463.server4u.cz |
vs372.server4u.cz |
vs512.server4u.cz |
vs438.server4u.cz |
vs1271.server4u.cz |
vs557.server4u.cz |
vs676.server4u.cz |
vs402.server4u.cz |
m177.server4u.cz |
vs508.server4u.cz |
m263-atlantis1.server4u.cz |
vs992.server4u.cz |
vs195.server4u.cz |
d154.server4u.cz |
vs203-2.server4u.cz |
cybers-web-alt.server4u.cz |
vs322.server4u.cz |
Same first word
server4u.se |
server4u.fr |
server4u.cz |
server4u.dk |
server4u.com |
server4u.eu |
server4u.co.il |
server4u.sk |
server4u.hu |
server4u.de |
server4u.ru |
server4u.at |
server4u.nl |
server4u.gr |
Similar names
DNS History
7 records (5 active, 2 former)
●NSns.web4u.cz2015-09-02 → 2026-03-21 · 5 obs
● 2017-01-23 23:25:32
○ 2017-07-24 02:14:24
● 2020-07-21 02:31:00
● 2026-03-21 04:16:12
○MXmail.server4u.cz2015-09-02 → 2017-09-22 · 4 obs
● 2017-09-22 16:12:42
○ 2019-08-24 14:29:54
○ 2026-03-21 04:16:12
○MXmx.web4u.cz2019-08-24 → 2020-07-21 · 5 obs
● 2019-08-24 14:29:54
● 2020-07-21 02:31:00
○ 2026-02-15 12:56:00
○ 2026-03-21 04:16:12
●MXmx1.mailchannels.net2026-02-15 → 2026-03-21 · 3 obs
● 2026-02-15 12:56:00
● 2026-03-21 04:16:12
●MXmx2.mailchannels.net2026-02-15 → 2026-03-21 · 3 obs
● 2026-02-15 12:56:00
● 2026-03-21 04:16:12
●A81.91.86.272015-09-02 → 2026-03-21 · 2 obs
● 2026-03-21 04:16:12
🔍 DNS Trace
📋 Delegation Chain
| Zone | Nameservers | Glue |
|---|---|---|
| cz | a.ns.nic.cz, b.ns.nic.cz, c.ns.nic.cz, d.ns.nic.cz | - |
| server4u.cz | ns.web4u.cz, ns2.web4u.cz | 4 records |
✅ Authoritative Response
Server: 85.207.53.12
NS records: ns.web4u.cz, ns2.web4u.cz
🔒 DNSSEC Status
🔐 Secure (DNSSEC validated)
Chain of trust verified from root to domain
⏱️ Timing
Total: 1112ms | Queries: -
📄 Records
| Type | Count | Sample Data |
|---|---|---|
| A | 1 | 81.91.86.27 |
| NS | 2 | ns.web4u.cz, ns2.web4u.cz |
| MX | 2 | mx1.mailchannels.net (pri: 10), mx2.mailchannels.net (pri: 10) |
| SOA | 1 | ns.web4u.cz admin.web4u.cz |
📌 Glue Records Collected
Total: 4
Out-of-bailiwick: 4 (ns.web4u.cz, ns.web4u.cz, ns2.web4u.cz...)
Analysis
Hierarchy
server4u.cz is the parent of vs397.server4u.cz, vs1269.server4u.cz, vs205.server4u.cz, m215.server4u.cz, m216-1.server4u.cz and several hundred other host names.
IP Addresses
server4u.cz maps to IP address 81.91.86.27.
Other host names, for instance www2.spravadomen.cz, sprava-domeny.cz, asp4you.cz, phpmyadmin.sprava-domeny.cz and spravadomen.cz share IP numbers with server4u.cz.
Name Servers
Two name servers ns2.web4u.cz and ns.web4u.cz are delegated to server4u.cz.
server4u.cz uses the same name server configuration as other domains, such as tipsport.at, laboratore.cz, moraviags.cz, eurofoam-sport.com and labmark.it.
Host names with two IPs:
ns2.web4u.cz points to 2a02:a40:100:28ff::12 and 85.207.53.12.
ns.web4u.cz points to 2001:1568:fd::241 and 185.14.224.241.
Mail Servers
Two mail servers handle server4u.cz: mx1.mailchannels.net and mx2.mailchannels.net.
server4u.cz shares the same mail server setup as other domains, including bitteliten.net, lofaengineering.com, mrbgc.com, mapstudios.org and bluecoatsingers.org.
server4u.cz shares some mail servers with other domains, at least partially, for instance thomconsulting.com.au.
Host names with a single IP address:
mx1.mailchannels.net points to 18.236.29.166
mx2.mailchannels.net points to 52.38.143.159