OCN (NTT Japan) mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), OCN (NTT Japan) is the mailbox provider for 140 domains — 0.02% of 675,489 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 140 domains in the Tranco top-1M use OCN (NTT Japan) (0.02% of domains with MX records).
- Snapshot date: 2026-09-24 — recomputed every day.
- Strongest TLD: .co.jp (48.6% of its domains).
- Region skew: Japan.
- Most co-used service: MailWise (mwprem).
- Directory category: mailbox provider.
Why OCN (NTT Japan) appears in this category
NTT Communications OCN business and ISP mailbox infrastructure in Japan.
We classify it as a mailbox provider from primary MX record (lowest preference) matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
What the data shows
95.7% of its domains sit outside the top 100,000 — a long-tail footprint spread across smaller sites. Its single largest TLD is .co.jp at 48.6% of its domains — a strong concentration across 8 TLDs overall. The service most often seen alongside it is MailWise (mwprem) (ESP), on 76.4% of its domains.
Where OCN (NTT Japan) sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 0 | 0.0% |
| Top 100,000 | 6 | 4.3% |
| Top 1,000,000 | 134 | 95.7% |
| Unranked | 0 | 0.0% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .co.jp | 68 | 48.6% | |
| .jp | 29 | 20.7% | |
| .or.jp | 22 | 15.7% | |
| .com | 16 | 11.4% | |
| .net | 2 | 1.4% | |
| .ne.jp | 1 | 0.7% | |
| .coop | 1 | 0.7% | |
| .info | 1 | 0.7% |
What OCN (NTT Japan) users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 140 domains.
| Type | Service | Domains | Share of OCN (NTT Japan) users |
|---|---|---|---|
| ESP | MailWise (mwprem) | 107 | 76.4% |
| ESP | Amazon SES | 6 | 4.3% |
| ESP | Repica WebCAS | 6 | 4.3% |
| ESP | FSI Email Security | 5 | 3.6% |
| ESP | BizMatrix | 4 | 2.9% |
| ESP | Salesforce | 4 | 2.9% |
| ESP | Cuenote | 3 | 2.1% |
| ESP | WiLL Mail | 3 | 2.1% |
| ESP | Q-Send | 3 | 2.1% |
| ESP | Kagoya (JP, sender) | 3 | 2.1% |
See the full OCN (NTT Japan) data page (KPI cards, trend, sample domains) →
Run a free inbox-placement test across Gmail, Outlook, Yahoo and more — see exactly where your mail lands and why.
Frequently asked questions
How many domains use OCN (NTT Japan)?
140 domains in the Tranco top-1M use OCN (NTT Japan) as their mailbox provider as of September 24, 2026 (0.02% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is OCN (NTT Japan) common enough to affect email deliverability testing?
OCN (NTT Japan) accounts for 0.02% of domains with MX records in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Which countries or TLDs use OCN (NTT Japan) most?
OCN (NTT Japan)'s largest TLD is .co.jp (48.6% of its domains); it appears across 8 TLDs in total.