Before configure this guidance, please make sure you’ve configured SPF checking from this link : https://imanudin.net/2016/03/11/zimbra-tips-how-to-enable-spf-checking-for-incoming-connection/. When you’ve done, by default will reject SPF only if configured fail (-). If SPF none or SPF soft fail, email will pass and given some score. If you want to block sender did not have SPF or soft fail, ..
Zimbra have been release new Zimbra Collaboration Suite version 8.5.0 and have some changes, especially in the Enforcing a match between FROM address and sasl username/Sender Must Login. Zimbra default configuration allows the user to relay emails using a different email address from user to authenticate with smtp. The following is example configuration on Thunderbird If your ..