The postmaster login is used by the email administrator to manage email accounts for a domain. Generally if you are hosting email for a single domain at Greatmail, you will be assigned a postmaster password to sign in. If you are managing email for multiple domains under a single hosting account, you will be assigned a webmaster user name and password to manage your email accounts. Using the postmaster login, you may manage your domain’s email accounts, autoresponders, forwards and spam filtering settings.
For advanced features such as provisioning additional domains or static IP addresses to the allowed relay list, you must contact Greatmail support.