1. Login to PDNS via http://dns.ipserverone.com/
2. Click on List Zones
3. Click on the listed domain / or domain of your choice.
4. Add A record for mail.domain.com and MX record pointing to mail.domain.com. For A record ‘Content‘, you will need to fill it with your smartermail login server IP, which can be obtained from the e-mail you received with the admin login.
Now you can access your e-mail logins via mail.domain.com