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AS25577MAINFRAME & CYBERNETIC SYSTEMS LIMITED

United KingdomRegistryRIPE NCCTypeCarrier

As of 27th September 2026, AS25577 (MAINFRAME & CYBERNETIC SYSTEMS LIMITED), a transit carrier registered in the United Kingdom with RIPE NCC, originates 54 IPv4 prefixes covering 55.3k addresses and 1 IPv6 prefix. By IPv4 address space that makes it the 4,249th-largest of the 79,523 networks we see originating IPv4, and the 94th-largest of 2,075 in the United Kingdom. It is seen behind 41 upstream networks, most often AS3257 (GTT Communications Inc.) and AS174 (Cogent Communications, LLC), and in front of 10 downstream networks. 20% of its announcements have a valid RPKI ROA; 2 are RPKI-invalid. 96% of its routes reach at least 90% of full-feed peers, and 2 prefixes are also originated by another network.

At a glance

IPv4 prefixes

54

IPv6 prefixes

1

IPv4 addresses

55.3k

IPv6 /64s

4.3B

Upstream graph

The networks AS25577 is seen behind, one and two hops out, drawn from real AS paths.

AS25577Toward the internet core
Upstream graph for AS25577: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS25577MAINFRAME & CYBER…This networkAS174Cogent Communicat…AS3257GTT Communication…AS6939Hurricane Electri…AS14537Continent 8 LLCAS18106Viewqwest Pte LtdAS1299Arelion (fka. Tel…AS151326DCConnect Communi…AS6667Elisa OyjAS398465Rackdog LLCAS20130Depaul UniversityAS2914NTT America, Inc.AS3356Lumen (Level 3)

Networks observed one and two hops upstream of AS25577 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

186

adjacent networks

Upstreams
4122%
Peers
13573%
Downstreams
105%

Networks carrying this one's traffic toward the rest of the internet. Listing the 40 seen on the most AS paths, of 41.

Upstreams of AS25577
NetworkCountryRelationshipPathsVantage pts
AS3257GTT Communications Inc.USPeer2,172111
AS174Cogent Communications, LLCUSPeer1,70537
AS6939Hurricane Electric LLCUSPeer45020
AS14537Continent 8 LLCUSPeer2442
AS18106Viewqwest Pte LtdSGPeer2362
AS4637Telstra International LimitedHKPeer2346
AS13030Init7 (Switzerland) Ltd.CHPeer2252
AS25091IP-Max SACHPeer2112
AS38880Micron21 Datacentre Pty LtdAUPeer2052
AS6667Elisa OyjFIPeer1862

Prefixes

All 55

The largest blocks AS25577 originates, widest first.

Largest prefixes originated by AS25577
PrefixAddressesVisibility
84.45.64.0/1816.4k80/81
84.45.32.0/198.2k80/81
84.45.16.0/204.1k80/81
81.27.88.0/212k81/81
84.45.8.0/212k80/81
109.104.120.0/212k81/81
5.133.184.0/221k80/81
37.58.24.0/221k80/81
81.27.80.0/221k80/81
81.27.88.0/221k80/81

Routing health

How AS25577'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

  • Valid20.0%11
  • Invalid3.6%2
  • No ROA76.4%42

Propagation

  • Globally propagated90% of full-feed peers or more96.4%53
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%3.6%2

Prefix sizes

IPv4 — 54 prefixes

IPv6 — 1 prefixes

  • /324.3B × /64100.0%1

Recent changes

Announcements that started or stopped since 28th Aug 2026.

No announcement by AS25577 started or stopped in this period.

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