Smartermail 5.x provides facility to enable or disable Greylisting for entire domain. Greylisting is used to block incoming spam mails. To enable or disable Greylisting option for entire domain, you will need to follow the below steps:

[1] Login to your Smartermail interface using admin username and password.

[2] Go to Domains -> All Domains and search for a domain name.

[3] Right click on the domain name and click on "Edit" option.

[4] Go to "Technical" tab and uncheck "Disable Greylisting" option to enable Greylisting and check this box to disable Greylisting.

[5] Save your setting.