A hard bounce is an email marketingEmail marketing, also known as Emailing, is a digital marketing strategy that uses email as its medium. It is one of the... More concept.
It refers to a notification which indicates that a message sent has not been received successfully. In contrast to a soft bounceA soft bounce is an email marketing concept. It refers to a notification which indicates that a message sent has not bee... More, a hard bounce is a notification of definitive failure, indicating that the email addressEmail addresses, also known as "electronic addresses" or simply "emails", represent a form of digital communication popu... More concerned cannot receive any email.
The main cause of this failure notification is the fact that the email address contacted does not exist (or no longer exists).
The hard bounce notification is generally sent to the email address from which the message was originally sent (the “FROM:” field in the header), by the SMTPSMTP stands for “Simple Mail Transfer Protocol”. Created in 1982, SMTP is an email transfer protocol used for... More server which was supposed to receive the email (the “TO:” field in the header).
In email marketing, it is common practice to customize the header of the email sent to modify the “Return-Path:” field, thus allowing you to indicate to which email address this bounce notification should be sent in the event of email delivery failure (replacing the sender address). The aim here is to centralize hard bounce messages to a specific email address, which will then be analyzed to identify all invalid addresses of a specific email campaign.
From a technical point of view, a bounce generally consists of a message customized by the SMTP server issuing it, together with a specific return code indicating the precise reason for the bounce. Among the return codes used by SMTP, “550 5.1.1” is the one most often used to designate a hard bounce.
The hard bounce rate is an important metric in email marketing for evaluating the quality of advertisers, which will be constantly monitored by email routersAn email router is an online service that simplifies and enriches (through statistics and tracking) the email marketing ... More. If the hard bounce rate is too high, this can be a legitimate reason for the email router to block mailings of one of his customers.
To ensure that an email address can be used and that it will not generate a hard bounce, an email checkerAn email verifier, also known as an email checker, is a software used to check an email address or a list of email addre... More could be used, which will provide this information before a true email is sent.