First things first
You will need a basic user account.
After this, you can request E-Mail domain access.

How the user accounts work
We have set up the user accounts to work a little differently, your username can be tied to multiple E-Mail domains, which essentially means "1 account per domain".

1. Authentication: no authentication
Some legacy E-Mail clients simply lack SMTP authentication, to tackle this issue we made some changes to the server.

Sending mail in this case requires you to whitelist your IP from the E-Mail domains management interface. Don't forget to set your Reply-To E-Mail address properly.

2. Authentication: username
This somewhat works like above, however you are authenticating properly, which means the correct headers are sent, we prefer this over not authenticating at all.

3. Authentication: username@domain.tld
This is the preferred way when sending mail within our environment.

Authentication Methods
The server will accept unathenticated connections (as long as the IP is whitelisted) as well as AUTH PLAIN and AUTH LOGIN

Public Internet Server Details
Host: mcp.mac.gdn
Port: 25, 2525

VesperNet Server Details
Host: one.mail.com
Port: 25, 2525