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Hostname

isp21.cz

Last fetched

isp21.cz resolves to 1 IPv4 address operated by AS25234 in CZ. WHOIS lists registrar:reg-active24 as the registrar.

Nutrition Label

WHISPER CANON · isp21.czRouting diversity1.5/10Peering density4.2/10MOAS conflict✓ noneThreat-feed listings10.0/10WHOIS transparency3.3/10Resolver footprint8.2/10canon.whisper.security/host/isp21.cz

Resolution chain

isp21.cz resolves to 1 distinct IPv4 address via WhisperGraph DNS data. Each row links to the IP, prefix, and announcing ASN.

IPPrefixASNOperatorCountry
31.15.10.14831.15.8.0/21AS25234—CZ

WHOIS identity

Registrar
registrar:reg-active24
Organization
ergotep, družstvo invalidů
Contact emails
—

Subdomains

2 observed subdomains of isp21.cz.

Subdomain
test01.isp21.cz
www.isp21.cz

Web-graph footprint

Distinct hostnames that link to or from isp21.cz in the public web crawl.

26 sites link to this hostname.

58 sites linked to from this hostname.

Sample inbound links

Sample outbound links

Threat posture

History

Mail and authentication

MX records

SPF policy

3 SPF mechanisms authorising senders for isp21.cz.

MechanismTarget
SPF_Aisp21.cz
SPF_INCLUDE_spf.mlsend.com
SPF_MXisp21.cz

Related pages

Pivot deeper into the graph from isp21.cz.

Cypher and MCP

Reproduce the resolution chain directly against graph.whisper.security:

MATCH (h:HOSTNAME {name: "isp21.cz"})-[:RESOLVES_TO]->(ip:IPV4)
      -[:ANNOUNCED_BY]->(ap:ANNOUNCED_PREFIX)
      -[:ROUTES]->(asn:ASN)-[:HAS_NAME]->(n:ASN_NAME)
RETURN ip.name AS ip, ap.name AS prefix, asn.name AS asn, n.name AS operator
LIMIT 20

Or query Whisper from your own LLM workflow via the Whisper MCP server.