.au is the country domain used in Australia. Across 560,378 .au addresses verified by BounceZero between April and October 2026, 36.5% were invalid, 6.3% catch-all, 17.6% unknown and 37.3% confirmed valid. The invalid share is far above the business average.
Every .au address BounceZero verified for customers between April and October 2026, beside the corpus benchmarks. The remainder of each row to 100% is risky and role results.
| Segment | Addresses | Invalid | Catch-all | Unknown | Confirmed valid |
|---|---|---|---|---|---|
| .au | 560,378 | 36.5% | 6.3% | 17.6% | 37.3% |
| All non-freemail domains (business and ISP) | 6,514,884 | 14.5% | 2.3% | 27.0% | 32.6% |
| Business domains only (consumer ISP and freemail excluded) | 1,269,919 | 22.9% | 9.4% | 22.5% | 40.3% |
| All freemail | 1,415,154 | 17.6% | 1.1% | 2.1% | 74.0% |
Non-freemail includes consumer ISP mailboxes; a business-only cut is on the benchmarks page. Method and every other cut: Lead List Quality Benchmarks 2026. Risky and role on the .au row: 2.4%.
The weakest large country segment: more than a third of addresses invalid and a notable catch-all share, driven by retired regional freemail brands and churned ISP mailboxes.
Australia is the weakest large country segment in the corpus because of retired regional freemail brands, ISP mailboxes that follow churned broadband contracts, and a gateway at the largest ISP that defers probes. Australian business domains verify reasonably well; the ISP addresses do not. The Spam Act requires consent or a business relationship for commercial email, with a narrow exception for addresses published for business purposes, so Australian lists need both a lawful basis and a sample verification before purchase.
On confirmed-invalid rate, .au ranks 1 of 23 country domains in the corpus, ahead of .us at 34.1%.
On unknown rate, .au ranks 12 of 23 country domains in the corpus, just behind .edu at 18.5%, ahead of .co at 15.3%.
On confirmed-valid share, .au ranks 16 of 23 country domains in the corpus, just behind .edu at 38.1%, ahead of .org at 36.2%.
How to read these rates: they are BounceZero's probe outcomes on customer lists over April to October 2026, not a census of .au mailboxes. Unknown and catch-all measure what verification could not confirm, which depends on the provider's gateway policy during the window as much as on the addresses. The lists are the ones customers chose to upload, so segments dominated by a few large uploads carry their age and source. Method and limitations: benchmarks page.
About one in 6 .au addresses cannot be confirmed either way. That is gateway behaviour, not a verdict; route those contacts to phone or LinkedIn and re-check after a week.
More than one in 3 .au addresses hard-fail. Use the domain as a staleness marker for the whole list, not just the segment.
6.3% of .au addresses sit behind a catch-all accept. Those cannot be confirmed; send to them only from a secondary domain at low volume.
37.3% of .au addresses confirmed as deliverable at verification time and can go straight to the primary sequence, with a re-check before every send.
Sample-verify any Australian list before buying it. Expect to lose a third of ISP addresses on first verification and hold catch-alls out of cold volume.
Role addresses such as info@ and sales@ make up 0.9% of .au addresses in the corpus. Role addresses rarely reach a person; prefer named contacts.
36.5% of 560,378 .au addresses verified by BounceZero between April and October 2026 were confirmed invalid, against 14.5% across non-freemail domains and 17.6% across freemail.
17.6%. Unknown means the mailbox could not be confirmed either way, usually because the gateway deferred the probe. BounceZero refunds unknown results; re-check after a week or use a second channel.
Partly: 6.3% of .au addresses sat behind a catch-all accept, so the server took any address and the mailbox could not be confirmed.
37.3% confirmed valid at verification time. Keep bounces under 2% and complaints under 0.3% on the send, and re-verify the segment before every send.
Upload the file and see valid, invalid, catch-all and unknown per row, with the .au segment against this benchmark. 100 free checks a month, unknowns refunded.
Ayoub built BounceZero's 5-stage validation pipeline, its dedicated BGP-announced IP infrastructure, and the Patroni HA PostgreSQL cluster behind every verification. Previously built high-volume email delivery infrastructure. Trained at 1337 Benguerir (École 42 network, 2019). Open-source: bgp_analyzer.
Invalid, catch-all and unknown rates per email provider and country domain, 2026
15,222 .at addresses verified April to October 2026
421,292 AT&T addresses verified April to October 2026
47,494 Bbox (Bouygues Telecom) addresses verified April to October 2026
28,040 .be addresses verified April to October 2026
134,384 BellSouth addresses verified April to October 2026
35,207 BigPond (Telstra) addresses verified April to October 2026
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