Currently success: true is a definitive answer that SMTP server acknowledges that it would receive email to a given address.
success: false could mean both rejection of a RCPT TO command and misconfiguration on client side, e.g. 554-Bad DNS PTR resource record. So success: false could give false negatives due to client misconfiguration.
It would be convenient to differentiate mailbox existence and middle step success flags. For example { exists: true|false|undefined, failed: 'CONNECT|EHLO|MAIL FROM|RCPT TO' } with exists set to boolean only when response is definitive.
Currently
success: true
is a definitive answer that SMTP server acknowledges that it would receive email to a given address.success: false
could mean both rejection of aRCPT TO
command and misconfiguration on client side, e.g.554-Bad DNS PTR resource record.
Sosuccess: false
could give false negatives due to client misconfiguration.It would be convenient to differentiate mailbox existence and middle step success flags. For example
{ exists: true|false|undefined, failed: 'CONNECT|EHLO|MAIL FROM|RCPT TO' }
with exists set to boolean only when response is definitive.