In order to avoid sending mail indefinitely to a wrong email address, Take the mail statistics for the recipient of the last 3 month : if more than 5 mails bounced (with interval of more than 1 week) the email is blacklisted.
In order to avoid sending mail indefinitely to a wrong email address, Take the mail statistics for the recipient of the last 3 month : if more than 5 mails bounced (with interval of more than 1 week) the email is blacklisted.