What is backupMX?

Backup MX is essentially a SMTP Server that will accept email for your domain if your primary SMTP mail server fails or goes offline.  When your server is offline the Backup MX SMTP server will accept the email and store it until the primary server (or alternative SMTP server) is back online and ready to accept emails again.  Then those emails on the Backup MX server will be delivered to the main server.

Backup MX provides clients and domains a fault tolerant email solution adding a strength to the companies disaster recovery/business continuity program.

How does it work?

When an email is sent to a recipient the email server uses DNS (Domain Name Service) MX (Mail eXchange) records to see which server handles the email for the domain.  The MX records have a priority of order assoicated with them.  The lower the number the higher the priority of the mail server.

Typically the lowest number is your primary mail server that handles your email.  If this server is unavailable then delivery is attempted to the next mail server in the MX list.  The next server being that with the second lowest priority.

This is where Backup MX (Backup SMTP) fits in.  You assign a MX record of a lesser proirity to your primary mail server and if that server becomes unavailable the backup smtp server will accept your email.

Note

Please note that you don't need to purchase or transfer a domain to prolateral in order to use these server.  You do however need access to your domain DNS records in order to add the backup MX server to the MX records.