Microsoft Outlook Question:

This is the server used only to send emails (to transport them from your email client program to the receiver). Most outgoing mail servers are using the SMTP protocol (Simple Mail Transfer Protocol) for sending emails. Depending on your network settings, the outgoing mail server can belong to your ISP or to the server where you setup your email account. As an alternative, you can use a subscription based SMTP server (like smtp.com), which will allow you to send emails from any email account you already own. Due to anti-spam reasons, most of outgoing mail servers will not let you send emails if you are not logged on their network. An open-relay server will allow you to use it for sending emails, no matter if you belong to its network group or not, thus it is a heaven for spammers.