According to Live Direct Marketing's daily Tranco top-1M scan (July 13, 2026), DynDNS Mailhop is the email service provider (ESP) for 174 domains — 0.03% of 617,702 SPF-publishing domains. Detection method: include: mechanisms in the SPF record.
DynDNS Mailhop is an email relay service operated by DynDNS, a company historically known for dynamic DNS hosting. Mailhop provides message relay functionality for organisations that explicitly authorise it via SPF records, enabling it to handle transmission of outbound or relayed mail.
Mailhop's infrastructure footprint is concentrated in smaller sites and organisations operating legacy or shared mail arrangements, predominantly in the .com domain space. Its frequent co-appearance with Microsoft 365 in SPF records suggests it often serves as a supplementary relay for organisations whose primary email platform is M365 but which require external relay capacity or integration with legacy mail systems.
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 2 | 1.1% |
| Top 10,000 | 2 | 1.1% |
| Top 100,000 | 12 | 6.9% |
| Top 1,000,000 | 128 | 73.6% |
| Unranked | 30 | 17.2% |
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 86 | 49.4% | |
| .org | 17 | 9.8% | |
| .net | 16 | 9.2% | |
| .co.uk | 6 | 3.4% | |
| .com.au | 4 | 2.3% | |
| .cl | 3 | 1.7% | |
| .io | 3 | 1.7% | |
| .ch | 2 | 1.1% | |
| .ca | 2 | 1.1% | |
| .com.mx | 2 | 1.1% |
Cross-tabulated from the same daily snapshot — the other email services seen on the same 174 domains.
| Type | Service | Domains | Share of DynDNS Mailhop users |
|---|---|---|---|
| Mailbox | Microsoft 365 | 47 | 27.0% |
| Mailbox | Unknown / Other | 36 | 20.7% |
| Mailbox | Self-Hosted | 35 | 20.1% |
| Mailbox | Google Workspace | 15 | 8.6% |
| Mailbox | Barracuda | 9 | 5.2% |
| Mailbox | Generic / unmatched (mx*.*) | 7 | 4.0% |
| ESP | Amazon SES | 16 | 9.2% |
| ESP | SendGrid (Twilio) | 13 | 7.5% |
| ESP | Zendesk | 12 | 6.9% |
| ESP | HubSpot | 10 | 5.7% |
Mailhop frequently appears in the mail infrastructure of organisations already committed to Microsoft 365. This architectural pattern—M365 as primary platform plus Mailhop as external relay—suggests organisations using it for specific mail flows that fall outside their M365 tenancy, legacy application integrations that predate their Microsoft migration, or particular sending paths that require independent relay handling. Because Mailhop operates at smaller scale than mainstream ESPs, organisations routing mail through it should monitor its reputation status independently; poor reputation assigned to Mailhop infrastructure affects all downstream senders relying on it, but equally, its smaller deployment footprint can mean it avoids the filtering challenges that accumulate at large shared services.
See the full DynDNS Mailhop data page (KPI cards, trend, sample domains) →
Test against Mailhop only if you are directly routing mail through it or investigating a sender that does—that is, if Mailhop appears in the relevant SPF record. For general deliverability monitoring, its smaller footprint means it affects only a niche subset of mail flows, so it is rarely a priority testing target unless you have specific reason to investigate it.
174 domains in the Tranco top-1M use DynDNS Mailhop as their email service provider (ESP) as of July 13, 2026 (0.03% of SPF-publishing domains), according to Live Direct Marketing's daily DNS scan.
DynDNS Mailhop accounts for 0.03% of SPF-publishing domains 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.
DynDNS Mailhop's largest TLD is .com (49.4% of its domains); it appears across 37 TLDs in total.