All emails passing through Mailinblack are subject to filtering, including emails sent via a mailing list.
When an email is sent through a mailing list, a header is added. According to the RFC standard, it is the "sender" header, and for Google, it is the "X-Original-Sender."
How are emails sent via a mailing list handled?
Any sender sending an email to a mailing list, whether they are part of it or not, is subject to filtering for each email sent and to the authentication request upon the first exchange.
If the option is disabled, verifications will be conducted on the sender's address. The sender will be subject to filtering for each of their emails. This may also skew verifications, as they will be performed on the mailing list server rather than the original sender's server.
If the option is enabled, verifications will be performed on the sender header only, i.e., the mailing list address, for each email sent. Once the verifications are completed and successful, if the sender (the mailing list address) is authorized, then all emails sent to the mailing list will be considered valid for the intended user.
On the interface, the address that will appear is the sender header.
To enable this option, log in to the Protect interface, go to the "General Settings" tab, and then to Email Filtering :
Then, check the option "Check mailing lists on with sender header."
