Set up an external email provider

Note:

To set up external email, first add a domain name to your site. See Change the site domain.

That i have done!

1. Select Site Settings > Site Domains and then select New MX Record from the More Actions menu. An MX record (mail exchanger record) is a record in the Domain Name System. It specifies a mail server responsible for accepting email messages on behalf of a recipient's domain.
2. Select the domain from the menu and select the Use External Service for Email option.
3. Enter the external mail server name.Example: ASPMX.L.GOOGLE.COM.
4. Click Save

My question: Which external mail server name do i have to enter if i want to use my Mac-Account (@mac.com, @me.com, @icloud.com)?