> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mailchannels.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Setup IceWarp

> Configure IceWarp to relay outbound mail through MailChannels Outbound Filtering using SMTP authentication and smart host settings.

This guide walks you through configuring IceWarp to relay all outbound mail through MailChannels Outbound Filtering.

## Prerequisites

* Access to the IceWarp administration interface
* Your MailChannels SMTP username and password

## Configure the relay

<Steps>
  <Step title="Set the relay server">
    In the IceWarp administration interface, navigate to **Mail** > **General** > **Delivery** and enable **Use Relay Server**.

    Enter the following in the relay server field, replacing the placeholders with your actual MailChannels credentials:

    ```text theme={null}
    <MailChannelsUsername>:<MailChannelsPassword>@smtp.mailchannels.net:25
    ```

    <img src="https://mintcdn.com/mailchannelscorporation/qgJx36-4nVXYStTm/images/setting-up-for-icewarp/APoC4PBpMJe1MHsSeqCCSt25ybrNztORgTBgA204BFuwmpBMBF-56N2F8S18s_z0skwHiFhXfiUlVWe3.jpg?fit=max&auto=format&n=qgJx36-4nVXYStTm&q=85&s=d276f147da0387bec933c95732ce51fa" alt="IceWarp relay server configuration" width="790" height="588" data-path="images/setting-up-for-icewarp/APoC4PBpMJe1MHsSeqCCSt25ybrNztORgTBgA204BFuwmpBMBF-56N2F8S18s_z0skwHiFhXfiUlVWe3.jpg" />
  </Step>

  <Step title="Add the X-AuthUser header">
    MailChannels uses the `X-AuthUser` header to identify the authenticated sender. Messages without this header are treated as forwarded mail and subject to different policies.

    Navigate to **Mail** > **Rules** and click **Add**. Configure the rule as follows:

    | Field          | Value               |
    | -------------- | ------------------- |
    | **Conditions** | All messages        |
    | **Actions**    | Edit message header |
    | **Header**     | `X-AuthUser:`       |
    | **Value**      | `%%auth_email%%`    |

    Enable the rule and click **Apply**.

    <img src="https://mintcdn.com/mailchannelscorporation/qgJx36-4nVXYStTm/images/setting-up-for-icewarp/Selection_463.jpg?fit=max&auto=format&n=qgJx36-4nVXYStTm&q=85&s=ee1a586c1885faba3bd9d58caa1b3237" alt="IceWarp X-AuthUser rule configuration" width="1177" height="744" data-path="images/setting-up-for-icewarp/Selection_463.jpg" />
  </Step>
</Steps>