$ query “AS1221” --type=asn → 1 result(s)

AS1221 · ASN-TELSTRA

Telstra Limited

AS1221 is operated by Telstra Limited and serves as a major transit provider, registered in Australia. The system announces a whopping 13.4 million IPv4 addresses (0.36% of routable IPv4 space), including a /11, and supports IPv6. Most of its address space is geolocated to Australia, with additional presence in Papua New Guinea and the United States, and smaller footprints in 2 additional countries. This AS has recently updated its prefix announcements.

  • Top 5% — Top 5% of all autonomous systems by reach and degree
  • Space Overlord — Over 10 million IPv4 addresses
  • #41 by Reach — Top 100 by customer cone size
  • #1 in Australia — Top 10 by reach within country

Basic Information

Country
🇦🇺 Australia
Category
Internet Service Provider
Network Role
Major Transit
Data Origin
Authoritative — Metadata from authoritative RIR registry (ARIN, RIPE, APNIC, etc.)
Last Changed
March 04, 2026
Last Seen
April 18, 2026 (active)

Prefix Summary

IPv4 Prefixes (raw / aggregated)
284 / 236
IPv6 Prefixes (raw / aggregated)
2 / 2
IPv4 Addresses
13 401 088
Largest IPv4 Prefix
/11 (2 097 152 addresses)
Largest IPv6 Prefix
/20
Geolocated Countries
🇦🇺 Australia (13 393 408 IPs), 🇵🇬 Papua New Guinea (8 192 IPs), 🇺🇸 United States (3 072 IPs) and 2 more
Prefix Changed
April 15, 2026

Reputation

Reputation
Good — 119 flagged IPs out of 13 401 088 total (0.00%)

Connectivity Summary

Upstream Providers
1 upstream providing transit
Peers
12 networks exchanging traffic without transit
Downstream Customers
286 downstreams buying transit
Unclassified
5 unclassified BGP neighbors
Degree
304 unique BGP neighbors
Reach
41 752 networks in customer cone

Upstream Providers (1)

  • AS4637 — ASN-TELSTRA-GLOBAL

Prefix Lists

IPv4 Prefixes (284 total)

  • 1.128.0.0/11 (2 097 152 addresses (/11 prefix))
  • 101.160.0.0/11 (2 097 152 addresses (/11 prefix))
  • 124.176.0.0/12 (1 048 576 addresses (/12 prefix))
  • 58.160.0.0/12 (1 048 576 addresses (/12 prefix))
  • 121.208.0.0/12 (1 048 576 addresses (/12 prefix))
  • 1.120.0.0/13 (524 288 addresses (/13 prefix))
  • 60.224.0.0/13 (524 288 addresses (/13 prefix))
  • 110.144.0.0/13 (524 288 addresses (/13 prefix))
  • 203.40.0.0/13 (524 288 addresses (/13 prefix))
  • 120.144.0.0/13 (524 288 addresses (/13 prefix))
  • 110.140.0.0/14 (262 144 addresses (/14 prefix))
  • 203.36.0.0/14 (262 144 addresses (/14 prefix))
  • 120.152.0.0/14 (262 144 addresses (/14 prefix))
  • 203.48.0.0/14 (262 144 addresses (/14 prefix))
  • 144.132.0.0/14 (262 144 addresses (/14 prefix))
  • 144.136.0.0/15 (131 072 addresses (/15 prefix))
  • 123.210.0.0/15 (131 072 addresses (/15 prefix))
  • 203.52.0.0/15 (131 072 addresses (/15 prefix))
  • 120.156.0.0/15 (131 072 addresses (/15 prefix))
  • 149.135.0.0/16 (65 536 addresses (/16 prefix))
  • 143.238.0.0/16 (65 536 addresses (/16 prefix))
  • 144.140.0.0/16 (65 536 addresses (/16 prefix))
  • 144.139.0.0/16 (65 536 addresses (/16 prefix))
  • 144.131.0.0/16 (65 536 addresses (/16 prefix))
  • 147.69.0.0/16 (65 536 addresses (/16 prefix))
  • 203.35.0.0/16 (65 536 addresses (/16 prefix))
  • 139.168.0.0/16 (65 536 addresses (/16 prefix))
  • 120.158.0.0/16 (65 536 addresses (/16 prefix))
  • 139.134.0.0/16 (65 536 addresses (/16 prefix))
  • 165.228.0.0/16 (65 536 addresses (/16 prefix))
  • 123.209.0.0/16 (65 536 addresses (/16 prefix))
  • 139.130.0.0/16 (65 536 addresses (/16 prefix))
  • 101.103.0.0/16 (65 536 addresses (/16 prefix))
  • 125.255.0.0/16 (65 536 addresses (/16 prefix))
  • 203.54.0.0/16 (65 536 addresses (/16 prefix))
  • 138.217.0.0/16 (65 536 addresses (/16 prefix))
  • 137.147.0.0/16 (65 536 addresses (/16 prefix))
  • 138.130.0.0/16 (65 536 addresses (/16 prefix))
  • 203.58.128.0/17 (32 768 addresses (/17 prefix))
  • 61.9.128.0/17 (32 768 addresses (/17 prefix))
  • 144.130.0.0/17 (32 768 addresses (/17 prefix))
  • 144.130.192.0/18 (16 384 addresses (/18 prefix))
  • 203.27.128.0/18 (16 384 addresses (/18 prefix))
  • 203.58.64.0/18 (16 384 addresses (/18 prefix))
  • 202.12.128.0/18 (16 384 addresses (/18 prefix))
  • 203.143.192.0/18 (16 384 addresses (/18 prefix))
  • 192.74.160.0/19 (8 192 addresses (/19 prefix))
  • 144.130.160.0/19 (8 192 addresses (/19 prefix))
  • 202.7.64.0/19 (8 192 addresses (/19 prefix))
  • 192.148.128.0/19 (8 192 addresses (/19 prefix))
  • and 186 more

IPv6 Prefixes (2 total)

  • 2001:8000::/20
  • 2401:a480::/48