subnet.im

AS2852CESNET z.s.p.o.

CzechiaRegistryRIPE NCCTypeEyeball

As of 26th September 2026, AS2852 (CESNET z.s.p.o.), an access network registered in Czechia with RIPE NCC, originates 26 IPv4 prefixes covering 858k addresses and 1 IPv6 prefix. By IPv4 address space that makes it the 511th-largest of the 79,516 networks we see originating IPv4, and the 4th-largest of 574 in Czechia. It is seen behind 44 upstream networks, most often AS21320 (GEANT Vereniging) and AS6939 (Hurricane Electric LLC), and in front of 19 downstream networks. Every one of its announcements has a valid RPKI ROA, and none are RPKI-invalid. 100% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

26

IPv6 prefixes

1

IPv4 addresses

858k

IPv6 /64s

34.4B

Upstream graph

The networks AS2852 is seen behind, one and two hops out, drawn from real AS paths.

AS2852Toward the internet core
Upstream graph for AS2852: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS2852CESNET z.s.p.o.This networkAS174Cogent Communicat…AS1853ACONETAS6939Hurricane Electri…AS21320GEANT VerenigingAS60606PRO-ZETA a.s.AS1299Arelion (fka. Tel…AS151326DCConnect Communi…AS18106Viewqwest Pte LtdAS20130Depaul UniversityAS2603NORDUnetAS3356Lumen (Level 3)AS39392SH.cz s.r.o.

Networks observed one and two hops upstream of AS2852 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.

Neighbouring networks

273

adjacent networks

Upstreams
4416%
Peers
21077%
Downstreams
197%

Networks carrying this one's traffic toward the rest of the internet. Listing the 40 seen on the most AS paths, of 44.

Upstreams of AS2852
NetworkCountryRelationshipPathsVantage pts
AS21320GEANT VerenigingNLPeer1,08928
AS6939Hurricane Electric LLCUSPeer98559
AS174Cogent Communications, LLCUSPeer75421
AS60606PRO-ZETA a.s.CZPeer32112
AS1853ACONETATPeer1804
AS7713PT Telkom Indonesia TbkIDPeer1623
AS6461Zayo BandwidthUSPeer1343
AS24482SG.GSSGPeer1293
AS20965GEANT VerenigingNLPeer1122
AS38880Micron21 Datacentre Pty LtdAUPeer1102

Prefixes

All 27

The largest blocks AS2852 originates, widest first.

Largest prefixes originated by AS2852
PrefixAddressesVisibility
146.102.0.0/1665.5k81/81
147.32.0.0/1665.5k81/81
147.33.0.0/1665.5k81/81
147.228.0.0/1665.5k81/81
147.230.0.0/1665.5k81/81
147.231.0.0/1665.5k81/81
147.251.0.0/1665.5k81/81
158.194.0.0/1665.5k81/81
158.196.0.0/1665.5k81/81
160.216.0.0/1665.5k81/81

Routing health

How AS2852's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.

RPKI origin validation

  • Valid100.0%27
  • Invalid0.0%0
  • No ROA0.0%0

Propagation

  • Globally propagated90% of full-feed peers or more100.0%27
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%0.0%0

Prefix sizes

IPv4 — 26 prefixes

IPv6 — 1 prefixes

  • /2934.4B × /64100.0%1

Recent changes

Announcements that started or stopped since 28th Aug 2026.

No announcement by AS2852 started or stopped in this period.

Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.