grendel.cz

.cz dns crawl

First seen 2026-05-31 · Last seen 2026-06-02 · ok HTTP/1.1 200 209 ms crawled 2026-06-01

CZ · 91.206.91.20 · AS196849 MO BYRTUS s.r.o.

Reputation 95/100 weak security headers

Classifying

HTML metadata

Title: Grendel a.s.
Description: Grendel a.s. - ISP, firewall, email, www

Technology

Server: nginx

Registration

Registrar

REG-INTERNET-CZ

Created

1996-09-08

Expires

2027-10-27 511 days left

Updated

2023-09-23

Name servers

ns2.he.net
ns3.grendel.cz
ns5.he.net
ns.grendel.cz
ns.inecnet.cz

DNS records live

NS

ns.grendel.cz
ns2.he.net
ns3.grendel.cz
ns5.he.net

MX

30 mspool.gts.cz
5 ns3.grendel.cz

Email authentication strong

SPF

v=spf1 include:vectorsight.net include:fairlynet.com -all

strict (-all)

DMARC

v=DMARC1; p=reject;

policy: reject (enforced)

DKIM

default: v=DKIM1; t=s; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC4u1ID+5DwIBHTJt4kpNYJJKx88870ifUX3oBOZ5wYYoCuHPZwEQBczbXa0VKGL7GVSAuSkX8A+ZAJcMAjsc5r…

selectors probed

Certificate (current)

R12

from 2026-05-25 to 2026-08-23

Expires in 81 days

Full certificate history on crt.sh ↗

HTTP security headers

Header hygiene 30/100 Checked live page: https://grendel.cz/

findings

missing HSTS
missing Content Security Policy
missing frame protection
missing content type protection
missing Referrer Policy
missing Permissions Policy