Sending E-Mails Using Both SMTP And DNS Servers

If both DnsServers and SmtpServers collections are non-empty, MailBee compares the priorities of the highest-priority DNS server and the highest-priority SMTP relay server. If the top priority SMTP server has the same or higher priority than the top priority DNS server, MailBee attempts to send mail using the SMTP relay server first. If it fails, the DNS MX lookup (direct send) is used. Higher priority value is actually lower integer value. I.e. 0 is the top priority while 999 is the lowest priority.

Thus, it is possible to easily combine both "direct send" and "send to relay SMTP server" methods to improve reliability of send mail operation even further.