SBCGlobal is a Legacy US ISP mailbox (AT&T, hosted by Yahoo). Across 232,302 SBCGlobal addresses verified by BounceZero between April and October 2026, 4.6% were invalid, 0.1% catch-all, 36.3% unknown and 18.0% confirmed valid. Unknown dominates because the gateway defers probes.
Every SBCGlobal 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 |
|---|---|---|---|---|---|
| SBCGlobal | 232,302 | 4.6% | 0.1% | 36.3% | 18.0% |
| 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% |
| All .net addresses | 1,252,193 | 17.6% | 0.6% | 28.8% | 19.9% |
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 SBCGlobal row: 41.0%.
SBCGlobal is a legacy AT&T brand now hosted on Yahoo, so the pattern matches att.net: low confirmed-invalid share, high unknown share from rate-limited probes. The addresses are old by definition, which means a large share of the unknowns are in fact dormant.
SBCGlobal belongs to the SBC Communications era before the AT&T merger and has not been issued for new customers in well over a decade. Any list that carries it in volume was compiled from records that old. The mailboxes that still work belong to long-standing customers, usually in Texas, California and the Midwest, and they are overwhelmingly personal. The segment has little B2B value beyond flagging the list's age.
On confirmed-invalid rate, SBCGlobal ranks 23 of 29 providers in the corpus, just behind PeoplePC at 5.6%, ahead of BellSouth at 4.5%.
On unknown rate, SBCGlobal ranks 10 of 29 providers in the corpus, just behind Yahoo Mail at 39.0%, ahead of Netcom at 35.5%.
On confirmed-valid share, SBCGlobal ranks 16 of 29 providers in the corpus, just behind iiNet at 18.9%, ahead of Yahoo Mail at 16.4%.
How to read these rates: they are BounceZero's probe outcomes on customer lists over April to October 2026, not a census of SBCGlobal 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.
Most SBCGlobal results are unknown because the gateway defers verification probes. Nothing in that number says the mailboxes are dead; it says email verification alone cannot clear this segment.
Only 4.6% of SBCGlobal addresses hard-fail, against 14.5% across non-freemail domains.
Catch-all is negligible on SBCGlobal (0.1%); when this provider does return valid, the mailbox accepted the probe itself rather than a blanket accept.
Only 18.0% of SBCGlobal addresses confirmed as live mailboxes. Those few go to the primary sequence; the segment as a whole is not a cold-email segment.
Note the risky and role share: 41.0% of SBCGlobal results landed there, which the four headline columns do not show. Read risky as 'deliverable but with a flag' and test it at low volume before trusting it.
Treat sbcglobal.net as a legacy segment: re-check unknowns once, then move anything still unconfirmed to a low-priority list. These contacts are rarely worth a cold sequence.
Role addresses such as info@ and sales@ make up 0.0% of SBCGlobal addresses in the corpus. Role addresses are rare here, as expected for a mailbox provider.
4.6% of 232,302 SBCGlobal addresses verified by BounceZero between April and October 2026 were confirmed invalid, against 14.5% across non-freemail domains and 17.6% across freemail.
36.3%. 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.
Not in practice: 0.1% of SBCGlobal addresses returned catch-all, so a valid verdict means the mailbox exists.
18.0% 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 SBCGlobal 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
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