AS9426 — WESTPAC-AS-AP Westpac Bank
AS9426 announces 17 IPv4 prefixes covering 17,920 addresses and 0 IPv6 prefixes.
About this network
AS9426 (WESTPAC-AS-AP) is held by Westpac Banking Corporation, one of Australia's four major banks. This is a corporate enterprise AS: the bank running its own routed address space for its branches, corporate sites and internet-facing services, not a network sold to anyone else.
What it's used for
The evidence is a large-enterprise pattern, and the neighbour count is what gives it away. The AS originates 55 IPv4 prefixes totalling 20,992 addresses but is observed with only 3 BGP neighbours. A carrier with 55 routes would be peered with dozens or hundreds of networks; a bank multihomed to two or three Australian transit providers for resilience would look exactly like this. The address inventory is dominated by 166.120.0.0/16, a legacy block registered to Westpac Banking Corporation, sliced up into a long tail of /19s, /20s, /22s and /24s — the deaggregation you get when an enterprise pins individual site or service ranges to particular upstreams. Alongside it sit smaller APNIC-region blocks (203.24.0.0/22, 203.24.4.0/22, 203.23.44.0/24) and 110.5.80.0/20 and its more specifics. No IPv6 prefixes appear in the RIS view.
Notable
- The core block 166.120.0.0/16 is registered to Westpac Banking Corporation and dates back to the early 1990s, an era when a large corporate could still obtain a /16 directly.
- 55 prefixes against only 3 neighbours is a strong enterprise signature: heavy internal deaggregation, almost no external peering.
- The AS carries no IPv6 in the observed routing table.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy.
Announced prefixes
- 110.5.80.0/23
- 110.5.84.0/22
- 110.5.90.0/23
- 166.120.0.0/22
- 166.120.5.0/24
- 166.120.7.0/24
- 166.120.64.0/23
- 166.120.68.0/22
- 166.120.72.0/21
- 166.120.80.0/20
- 166.120.164.0/22
- 166.120.200.0/22
- 166.120.212.0/22
- 166.120.216.0/22
- 203.16.39.0/24
- 203.23.44.0/24
- 203.24.0.0/21
Upstream networks
Adjacent networks
awaiting query
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