How to add List-Unsubscribe header
To implement the opt-out option in your email header, your email server must first be configured. For example, this is how to add the list-unsubscribe header to all outgoing emails using Postfix: in /etc/postfix/main.cf , set header_checks to: header_checks = regexp:/etc/postfix/list_unsub_header Copy create a list_unsub_header file in /etc/postfix/ and add the following: /^Content-Transfer-Encoding:/i PREPEND List-Unsubscribe: mailto:<sender-email-address>?subject=unsubscribe> " Copy Restart Postfix it with service postfix restart Copy or / etc / init .d / postfix restart Copy Contact your email administrator to insert this option for your particular server. If you use an email service provider, you can ask them to insert the list-unsubscribe header into your email. Or you can do this yourself, using the ESP’s documentation. To accomplish this, you will have to choose between two types of unsubscribing methods: mailto ...