On 03 Jul 2020, at 02:53, Ralph Seichter <ra...@ml.seichter.de> wrote: > * SysAdmin EM: > >> The user is using as From Header "gmail.com" which is very wrong.
No, that is not at all wrong, much less "very" wrong. It is not malformed. It is not an error in SMTP. It may be something that you do not want to allow, but that is quite a different thing. >> I am about to use the spf check for these cases, through the >> "policy-spf" component. That is not the solution. > Assuming that only authenticated users may send email using this Postfix > instance, you may want to look into the "smtpd_sender_login_maps" config > parameter as well. I think you want reject_authenticated_sender_login_mismatch (assuming only authenticated users are allowed to send mail, which should be the case on ever mail server). That does require setting up a map to check the login against the from, but I think that is straightforward. But as I said, I don't do this to my users, so I don't have an example config. -- Im finding's you'r mis'use of apostrophe's disturbing.
