KB00030302 Sending Mail without a Smart Host
A Smart Host
is a machine that accepts mail from you and then passes it on to the server most appropriate for it's recipient. This is the machine listed in Options | Outgoing Mail...
However if you are having probelms with your outgoing mail, it may be useful to bypass the smart host. The alternative delivery method is MX Resolution (where Mailtraq acts as a smart host and determines the mail server itself). MX Resolution can have many advantages (such as greater speed and reliability) but those are discussed elsewhere. There are cases where it is simply not possible to use a smart host, such as where you are using multiple ISPs and cannot rely on their smart hosts accepting your messages (when connecting with the other ISP).
To use MX Resolution, go to Options | Outgoing Mail... and click 'Use MX Resolution using the DNS servers below'.