> For the complete documentation index, see [llms.txt](https://docs.unimarket.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.unimarket.com/documentation/general-technical/email-authentication.md).

# Email Authentication

Unimarket uses **Postmark** to manage email delivery, ensuring high security, reliable delivery rates, and professional bounce handling. To verify that emails sent by the system are authorized by your organization, Unimarket utilizes **DKIM** (DomainKeys Identified Mail) and offers a **Custom Return Path** configuration.

## Email Authentication via DKIM

DKIM is the industry standard for email authentication. It uses a digital signature to prove to the recipient's mail server that the email was indeed sent by an authorized sender and has not been altered in transit. This setup ensures that when a supplier receives a PO notification, it appears to come directly from your domain (e.g., `procurement@customerdomain.com`).

## Understanding "Mail From" vs. "From"

By default, email clients may display Unimarket emails in two different ways depending on your technical setup:

* **Standard Setup (Default)**: Unimarket sets the "MAIL FROM" header to `bounce@customer.unimarket.com`. This ensures that if an email bounces, Unimarket can track it.
  * **User Experience**: The recipient may see `example@customerdomain.com via unimarket.com`.
* **Custom Return Path (Recommended)**: This authorizes Unimarket to send emails entirely on your behalf.
  * **User Experience**: The recipient sees only `example@customerdomain.com`. The "via Unimarket" label is removed.

## Return Path Setup (White Labeling)

Configuring a custom Return Path aligns your "MAIL FROM" address with your "FROM" address. This is the best way to prevent your emails from being flagged as spam by aggressive filters.

### 1. DNS Configuration (CNAME)

You must create a **CNAME** entry in your DNS settings that points your custom bounce domain to Unimarket.

* **Target Domain**: `bounce.customerdomain.com`
* **Points to**: `unimarket.com`

### 2. Domain Alignment

The Return Path must share the same suffix as your primary email domain.

* **If your email is**: `user@customerdomain.com`
* **Your Return Path should be**: `bounce@pm.customerdomain.com` or `bounce@bounce.customerdomain.com`.

## Implementation Steps for Administrators

1. **Coordinate with IT**: Provide your IT or Network team with the CNAME requirements mentioned above.
2. **Access Settings**: Once the DNS record is live, go to **Administration > Settings > Profile**.
3. **Enter Return Path**: Locate the **Email Delivery Authentication** section and enter your Return Path address.
4. **Validate**: Click the **Validate Return Path** button. The system will check your DNS to ensure the CNAME is correctly mapped.

## Benefits of Custom Return Path

* **Professional Branding**: Removes the "via unimarket.com" tag from the sender field.
* **Improved Deliverability**: Higher "sender reputation" since the email headers are fully aligned with your brand.
* **DMARC Compliance**: Helps your organization meet strict DMARC policies by ensuring the Return Path domain matches the From domain.

{% hint style="info" %}
Email authentication (DKIM and Return Path) works alongside SPF at the DNS level. See [Simplifying SPF Maintenance](/documentation/general-technical/simplifying-spf-maintenance.md) for details on authorizing Unimarket's mail servers via SPF.
{% endhint %}


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