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Block fake "From: " emails

Posted: Fri Jan 11, 2019 12:08 pm
by 7224jobe
Hello everybody,
I read and applied some antispam / antispoofing suggestions from zimbra wiki, but there is a spoofing situation that I can not still block. Here is an example:

Code: Select all

root@remoteserver: telnet zimbraserver.com 25

helo spamtest
250 zimbraserver.com
MAIL FROM: spammer@live.com
250 2.1.0 Ok
RCPT TO: userA@zimbraserver.com
250 2.1.5 Ok
DATA
354 End data with <CR><LF>.<CR><LF>
From: User B <spammer@live.com>
To: User A <userA@zimbraserver.com>
Subject: Please reply!!!

Reply to me!


User A in his Zimbra webmail sees a mail from "User B", only if he moves his mouse cursor over "User B" label can notice that the email address is "spammer@live.com" instead of "userA@zimbraserver.com". Even if he replies to the email only "User B" label appears.
So is there a way to enforce a match between MAIL FROM: telnet command and "From:" mail header?