Disable Sender Addresses Verification
Edit a mailbox and select "Allow to send as *".
For historical reasons we kept the old and deprecated guide below:
Deprecated guide (DO NOT USE ON NEWER MAILCOWS!)¶
This option is not best-practice and should only be implemented when there is no other option available to achieve whatever you are trying to do.
Simply create a file
data/conf/postfix/check_sasl_access and enter the following content. This user must exist in your installation and needs to authenticate before sending mail.
data/conf/postfix/main.cf and find
check_sasl_access hash:/opt/postfix/conf/check_sasl_access like this:
smtpd_sender_restrictions = check_sasl_access hash:/opt/postfix/conf/check_sasl_access reject_authenticated_sender_login_mismatch [...]
Run postmap on check_sasl_access:
docker compose exec postfix-mailcow postmap /opt/postfix/conf/check_sasl_access
Restart the Postfix container.