container-server/services/proxy/autoconfig/mail/config-v1.1.template.xml

<clientConfig version="1.1">
    <emailProvider id="${BASE_DOMAIN}">
        <domain>${BASE_DOMAIN}</domain>
        <displayName>${BASE_DOMAIN} Mail</displayName>
        <incomingServer type="imap">
            <hostname>post.${BASE_DOMAIN}</hostname>
            <port>143</port>
            <socketType>STARTTLS</socketType>
            <authentication>password-cleartext</authentication>
            <username>%EMAILADDRESS%</username>
        </incomingServer>
        <outgoingServer type="smtp">
            <hostname>post.${BASE_DOMAIN}</hostname>
            <port>587</port>
            <socketType>STARTTLS</socketType>
            <authentication>password-cleartext</authentication>
            <username>%EMAILADDRESS%</username>
        </outgoingServer>
    </emailProvider>
</clientConfig>