How to block Email from postfix

I'm using postfix to send and receive mail. I want to block Vietnamese Subject but do not know how to configure. Please help me!

Thank you,

Hi hungvx2,

specify the file in main.cf that holds header_checks. edit main.cf with your favorite editor and add as below.

Quote:

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header_checks = regexp:/etc/postfix/header_checks

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Then edit /etc/postfix/header_checks and Append:

Quote:

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/^Subject:.*Vietnamese/ DISCARD

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Restart postfix.