# MailProtocol

Location: [gRPC API](https://developer.m-files.com/APIs/gRPC-API/index.md) > [Reference](https://developer.m-files.com/APIs/gRPC-API/Reference/index.md) > [Enums](https://developer.m-files.com/APIs/gRPC-API/Reference/Enums/index.md)

HTML version: https://developer.m-files.com/APIs/gRPC-API/Reference/Enums/MFiles.MailProtocol/

Mail protocol enumeration.

- **Full name:** `MFiles.MailProtocol`
- **Proto file:** [`mfiles/enums.proto`](https://developer.m-files.com/APIs/gRPC-API/downloads/proto/mfiles/enums.proto)

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## Values

| Name | Number | Description |
|---|---|---|
| <a id="v-MAIL_PROTOCOL_NONE"></a>`MAIL_PROTOCOL_NONE` | 0 | Undefined. |
| <a id="v-MAIL_PROTOCOL_POP"></a>`MAIL_PROTOCOL_POP` | 1 | POP3. |
| <a id="v-MAIL_PROTOCOL_IMAP"></a>`MAIL_PROTOCOL_IMAP` | 2 | IMAP4. |
| <a id="v-MAIL_PROTOCOL_EXCHANGE"></a>`MAIL_PROTOCOL_EXCHANGE` | 3 | Exchange interface (EWS). DEPRECATED, DO NOT USE. |
| <a id="v-MAIL_PROTOCOL_REST_API"></a>`MAIL_PROTOCOL_REST_API` | 4 | Microsoft Graph plugin. |
| <a id="v-MAIL_PROTOCOL_IMAP4_PLUGIN"></a>`MAIL_PROTOCOL_IMAP4_PLUGIN` | 5 | Aspose.Email IMAP4 plugin. |

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## Used in fields

- [`MailSource.protocol`](https://developer.m-files.com/APIs/gRPC-API/Reference/Messages/MFiles.MailSource/index.md#f-protocol): The e-mail protocol to use.