Detail
Yes. When you run the WorkgroupMail setup program you can choose the option for Internal Mail Only. This setup just requires that you enter the organisation name, a contact name and an email address. The email address will be used to configure some of the main settings in the mail server, such as the domain name and the first user account. The domain part of the email address can be a fictitious address of your choice as the mail will be restricted to your local network. An example email address could be john@mycompany.int.
You will not receive any mail from the internet and as long as you do not configure any DNS servers in the smarthost settings, you will also not be able to send external mail. In order to stop WorkgroupMail accepting any messages destined for the internet, Relaying must be disabled. In the Relay Control Settings, Choose the option “This server does not relay messages for foreign domains…” and delete all trusted host addresses.
For WorkgroupMail v7 Enterprise and WorkgroupMail v8 edit the properties for each user account, click on the Account Restrictions tab and check the option “This user cannot send mail to the outside world”.