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AS1221Telstra Limited

AustraliaRegistryAPNICTypeEyeball

As of 10th November 2026, AS1221 (Telstra Limited), an access network registered in Australia with APNIC, originates 281 IPv4 prefixes covering 13.4M addresses and 2 IPv6 prefixes. By IPv4 address space that makes it the 55th-largest of the 80,723 networks we see originating IPv4, and the largest of 1,696 in Australia. It is seen behind 7 upstream networks, most often AS4637 (Telstra International Limited) and AS58511 (Swoop (Anycast Global Backbone)), and in front of 298 downstream networks. 45% of its announcements have a valid RPKI ROA, and none are RPKI-invalid. 98% of its routes reach at least 90% of full-feed peers, and 3 prefixes are also originated by another network.

At a glance

IPv4 prefixes

281

IPv6 prefixes

2

IPv4 addresses

13.4M

IPv6 /64s

17.6T

Upstream graph

The networks AS1221 is seen behind, one and two hops out, drawn from real AS paths.

AS1221Toward the internet core
Upstream graph for AS1221: 11 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS1221Telstra LimitedThis networkAS4637Telstra Internati…AS4826Vocus Connect Int…AS35280F5 Networks SARLAS38880Micron21 Datacent…AS58511Swoop (Anycast Gl…AS16552Tiggee LLCAS32590Valve CorporationAS2914NTT America, Inc.AS1299Arelion (fka. Tel…AS9002RETN LimitedAS3491PCCW Global (HK) …

Networks observed one and two hops upstream of AS1221 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

626

adjacent networks

Upstreams
71%
Peers
32151%
Downstreams
29848%

Networks carrying this one's traffic toward the rest of the internet.

Upstreams of AS1221
NetworkCountryRelationshipPathsVantage pts
AS4637Telstra International LimitedHKPeer163,238135
AS58511Swoop (Anycast Global Backbone)AUPeer12,1462
AS35280F5 Networks SARLFRPeer7,0436
AS38880Micron21 Datacentre Pty LtdAUPeer721
AS4826Vocus Connect International BackboneAUPeer2623
AS10026Telstra Global Internet Services Network BlocksJPPeer211
AS7545TPG Telecom LimitedAUPeer52

Prefixes

All 283

The largest blocks AS1221 originates, widest first.

Largest prefixes originated by AS1221
PrefixAddressesVisibility
1.128.0.0/112.1M74/76
101.160.0.0/112.1M74/76
58.160.0.0/121M74/76
121.208.0.0/121M74/76
124.176.0.0/121M74/76
1.120.0.0/13524k74/76
60.224.0.0/13524k74/76
110.144.0.0/13524k74/76
120.144.0.0/13524k74/76
203.40.0.0/13524k74/76

Routing health

How AS1221'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

  • Valid44.9%127
  • Invalid0.0%0
  • No ROA55.1%156

Propagation

  • Globally propagated90% of full-feed peers or more97.5%276
  • Partially propagated40% to 90%1.1%3
  • Seen by few peersUnder 40%1.4%4

Prefix sizes

IPv4 — 281 prefixes

IPv6 — 2 prefixes

  • /2017.6T × /6450.0%1
  • /4865.5k × /6450.0%1

Recent changes

Announcements that started or stopped since 11th Oct 2026.

11 announced and 11 withdrawn in all; the most recent are shown.

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