MX Provider Detection
Mailthentic analyzes MX records to identify the email service provider behind each domain. This detection influences how results are interpreted and scored.
Detected Provider Types
| Provider | Examples | Behavior |
|---|---|---|
| Google Workspace | gmail.com, custom domains using Google | Always returns 250 for RCPT TO — cannot confirm individual mailboxes. Results marked as "unconfirmed." |
| Microsoft 365 | outlook.com, hotmail.com, custom domains using Microsoft | Similar to Google — always accepts recipients. Results marked as "unconfirmed." |
| Yahoo Mail | yahoo.com, ymail.com, aol.com | Returns definitive accept/reject for individual mailboxes. |
| ProtonMail | protonmail.com, proton.me | Returns definitive accept/reject responses. |
| Custom SMTP | Self-hosted, lesser-known providers | Behavior varies — results depend on individual server configuration. |
| Unknown | Unrecognized MX patterns | Treated as custom SMTP. |
Why Provider Detection Matters
Google Workspace and Microsoft 365 are classified as "ambiguous" providers because their SMTP servers accept all recipients during the verification handshake. A "250 OK" from these providers doesn't mean the mailbox exists — it simply means the server accepted the command.
Mailthentic accounts for this by:
- Marking results from ambiguous providers as "deliverable_unconfirmed" instead of "deliverable_confirmed."
- Assigning a lower confidence score (78% vs. 97%).
Consumer vs. Business Classification
Beyond provider detection, Mailthentic also classifies domains as consumer (e.g., gmail.com, yahoo.com) or business (custom domains). This helps you segment results for different use cases — for instance, B2B outreach typically targets business domains.
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