Default mail domain name
The default mail domain name for the server, which usually matches the default MX record. For example, if you have configured mail.example.com in your DNS to point to your mail server, then you would enter this here. If a host name has been specified for an IP address on the server, then that value will override this host name.
DNS Address
The DNS that the local machine uses. If using more than one DNS, separate the addresses with a space character. If the SMTP service fails to connect to the first DNS, it will try the second or subsequent DNS. Use the DNS that is configured for the local network. Remember that this is not necessarily the DNS of where the domain name is registered.
Specify the email address when sending notifications
The address from which notifications are sent. When MailEnable sends out email such as message delivery delays, or delivery failures, it will use this address as the "from" email address. Usually this would be postmaster@example.com (substitute your domain here). Make sure this is a valid email address.
Enable NTLM Authentication (Professional and Enterprise Editions only)
If this feature is enabled then secure authentication between the server and the supported client is enabled. This will allow the server to accept requests from the client to use secure transmissions for the authentication method. The client also has to be enabled to use this secure authentication. For example, in Outlook the feature is called SPA 'Secure Password Authentication'.
Enable CRAM MD5 Authentication (Professional and Enterprise Editions only)
CRAM-MD5 Challenge-Response Authentication Mechanism is intended to provide an authentication extension that neither transfers passwords in clear text nor requires significant security infrastructure in order to function. Only a hash value of the shared password is ever sent over the network, thus precluding plaintext transmission.