How To Block Email Spoofing by Display Name
Please try below tips.
su - zimbra
vi /opt/zimbra/conf/from_checks
Fill with the following line
/^From:(.*@)+(.*@)/ HOLD it looks like you are spam
Note : If you receive email that having @ in the display name, email will be hold and you will getting information “it looks like you are spam” in the log. You can change HOLD with another method like DISCARD or REJECT.
Run the following command to add header check and restart postfix
zmprov ms `zmhostname` zimbraMtaHeaderChecks "pcre:/opt/zimbra/conf/postfix_header_checks,pcre:/opt/zimbra/conf/from_checks"
postfix reload
The following is an example email log that use @ in the display name
D6CAE2811C34: hold: header From: "imanudin@example.net" <spam@spam.xyz> from unknown[120.xxx.xxx.xx]; from=<spam@spam.xyz> to=<cilox@example.com> proto=ESMTP helo=: it looks like you are spam
Nov 1 23:45:45 myzimbra postfix/cleanup[17284]: D6CAE2811C34: message-id=<c8432028-4616-fcea-2280-699b7e22058e@spam.xyz>
Exmaple in mailq
[zimbra@myzimbra ~]$ mailq
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
D6CAE2811C34! 626 Thu Nov 1 23:45:45 spam@spam.xyz
cilox@imanudin.com
-- 1 Kbytes in 1 Requests.
In the Queue ID, have a ! sign (exclamation mark). It’s mean email holds. You can delete them (if that email is spam) or you can release them (if that email is not spam).
su - zimbra
vi /opt/zimbra/conf/from_checks
Fill with the following line
/^From:(.*@)+(.*@)/ HOLD it looks like you are spam
Note : If you receive email that having @ in the display name, email will be hold and you will getting information “it looks like you are spam” in the log. You can change HOLD with another method like DISCARD or REJECT.
Run the following command to add header check and restart postfix
zmprov ms `zmhostname` zimbraMtaHeaderChecks "pcre:/opt/zimbra/conf/postfix_header_checks,pcre:/opt/zimbra/conf/from_checks"
postfix reload
The following is an example email log that use @ in the display name
D6CAE2811C34: hold: header From: "imanudin@example.net" <spam@spam.xyz> from unknown[120.xxx.xxx.xx]; from=<spam@spam.xyz> to=<cilox@example.com> proto=ESMTP helo=: it looks like you are spam
Nov 1 23:45:45 myzimbra postfix/cleanup[17284]: D6CAE2811C34: message-id=<c8432028-4616-fcea-2280-699b7e22058e@spam.xyz>
Exmaple in mailq
[zimbra@myzimbra ~]$ mailq
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
D6CAE2811C34! 626 Thu Nov 1 23:45:45 spam@spam.xyz
cilox@imanudin.com
-- 1 Kbytes in 1 Requests.
In the Queue ID, have a ! sign (exclamation mark). It’s mean email holds. You can delete them (if that email is spam) or you can release them (if that email is not spam).
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