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Network report

Who holds an IP address, prefix or AS number, how it is routed (origin AS, RPKI, IRR), its reverse DNS, blocklist listings and PeeringDB record, with what to fix first.

IP address, prefix or AS number

AS2852 · 

curl -s "https://thenetworkery.com/api/v1/network-report?query=AS2852"
JSON Docs

Warning: AS2852 (CESNET2 CESNET z.s.p.o.) announces 27 IPv4 and 1 IPv6 prefixes. 1 warning

AS pageAS2852
HolderCESNET2 CESNET z.s.p.o.
AllocationRIPE NCC, Czechia (CZ), allocated 1993-12-20
Prefixes (IPv4 / IPv6)27 / 1
RPKI valid100% (28 / 28)
Upstreams and peers63
Peering policySelective

What to fix

  1. Warning

    No public NOC, policy or technical contact.

    Other networks use these addresses to set up peering and to reach you during an incident.

    Fix: Add a role contact (for example noc@ or peering@ an address you monitor) with visibility Public.

    Open in PeeringDB lookup

Checks

Routing and RPKI AS2852 announces 27 IPv4 and 1 IPv6 prefixes.
  • Pass: AS2852 announces 27 IPv4 and 1 IPv6 prefixes.
  • Pass: All 28 announced prefixes are RPKI valid.
  • Pass: Every announced prefix has an IRR route object.
  • Info: 63 upstreams and peers, 28 downstream networks seen.
HolderCESNET2 CESNET z.s.p.o.
IPv4 prefixes27
IPv6 prefixes1
RPKI28 valid
Downstream networks28

Upstreams and peers seen to the left 63

AS6939 Hurricane Electric AS21320 GEANT IAS AS174 Cogent Communications, Inc. AS1853 ACOnet AS60606 Blindspot Technologies AS6461 Zayo AS20965 GEANT R&E AS20723 AVONET AS5405 Inter.link AS8218 Zayo Europe AS35280 F5 Inc. AS34549 meerfarbig GmbH & Co. KG

Announced prefixes 28

78.128.128.0/17 146.102.0.0/16 147.32.0.0/16 147.33.0.0/16 147.228.0.0/16 147.230.0.0/16 147.231.0.0/16 147.231.150.0/24 147.251.0.0/16 158.194.0.0/16 158.196.0.0/16 160.216.0.0/16 160.217.0.0/16 185.8.160.0/22 193.84.32.0/20 193.84.53.0/24 193.84.55.0/24 193.84.56.0/21 193.84.80.0/22 193.84.104.0/22 193.84.116.0/23 193.84.160.0/20 193.84.192.0/19 193.84.192.0/20 193.84.208.0/20 195.113.0.0/16 195.178.64.0/19 2001:718::/29

Source: RIPEstat (RIPE NCC RIS, Routinator, IRR); AS names: Team Cymru

Open in ASN & BGP prefix lookup
Registration Found at rdap.db.ripe.net.
  • Pass: Found at rdap.db.ripe.net.
NameCESNET2
HandleAS2852
RangeAS2852
Statusactive
Registered2002-06-22T23:41:57Z
Last changed2026-09-13T21:22:38Z
Abuse contactabuse@cesnet.cz
Allocation
Registry (RIR)RIPE NCC
CountryCzechia (CZ)
Delegated on1993-12-20
StatusAllocated
Delegated rangeAS2852

Source: RIR delegation data, updated daily. The country is where the range was registered, not necessarily where it is used.

Contacts
RoleNameEmail
registrant AS2852-MNT
registrant CESNET z.s.p.o.
registrant RIPE-NCC-END-MNT
abuse CESNET z.s.p.o. Network Administrators abuse@cesnet.cz

Source: https://rdap.db.ripe.net/autnum/2852. Registration data from rdap.db.ripe.net, shown under its terms of use (terms): not for marketing or bulk collection. Personal contacts in this registry are not shown.

Open in WHOIS / RDAP lookup
PeeringDB No public NOC, policy or technical contact.
  • Pass: AS2852 is in PeeringDB as CESNET.
  • Info: Peering policy: Selective.
  • Info: Present at 3 internet exchanges with 4 ports (450G in total).
  • Warning: No public NOC, policy or technical contact.
NetworkCESNET
AS numberAS2852
TypeEducational/Research, Europe
Websitehttps://www.cesnet.cz
IRR as-setRIPE::AS2852:AS-CESNET-GOOGLE
Prefixes (IPv4 / IPv6)300 / 100
Traffic500-1000Gbps, Balanced
Peering policySelective
LocationsNot Required
Ratio requiredNo
ContractsNot Required
Looking glasshttps://lg.cesnet.cz
Last updated2026-11-02

Source: PeeringDB. Results are cached for an hour.

Open in PeeringDB lookup