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, ..
Most of spam email sent from public IP who did not have PTR/Reverse DNS. What is PTR/Reverse DNS, you can find more information from Wikipedia 😀 : https://en.wikipedia.org/wiki/Reverse_DNS_lookup If you have Zimbra and want to enable PTR/Reverse DNS lookup for incoming, you can perform the following command su – zimbra zmprov mcf +zimbraMtaRestriction "reject_unknown_client_hostname" Please wait ..
From previous article, you can configure and validate DKIM records on Zimbra which is used to increase email reputation. The configuration will increase reputation for outgoing email. But, how to enable DKIM/DomainKeys checking for incoming connection? By enable DKIM/DomainKeys checking, you can reject every incoming email who did not have DKIM/DomainKeys. By default, Zimbra only configure OpenDKIM as ..
Many ways to secure email delivery. One of them is use TLS connection/encrypted when sending email. The encryption connection will make connection between email server more secure. This guidance will explain step by step how to check smtp outgoing already use encryption or not. # Checking Header Please try to send email to Gmail or Yahoo and check ..
I have condition in my clients where all outgoing email from their server do relay into Relay server. This caused usually Public IP got blacklisted by RBL. I am perform the relay configuration by use this guidance : https://imanudin.net/2014/09/18/how-to-configure-outgoing-smtp-authentication-on-zimbra-8-5/ All email to outside well fine until found problem when sending email to some clients and getting error “too ..