ASPMXASPMX is an ASP component that provides simple DNS lookup of mail exchanger MX records. This is useful in applications where you need to know the hostname of the mail exchanger(s) for a given domain. For example, if someone provides you with an email address like joebloggs@microsoft.com, ASPMX will lookup the names and priorities of the mail servers that are registered as mail exchangers for microsoft.com. The Component can also be used to validate an email address. It does this by attempting to connect to the lowest cost mail exchanger and simulating an SMTP transmission for the email address passed. In general, this can be used to determine whether the email address joebloggs@microsoft.com really exists (or at least whether mail will be accepted for the user).