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docs/u_e-postfix-anonym_headers.md

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-**As of October the 15th, 2018 this is enabled by default.**
-
-To disguise your users details like IP, email client, etc. we have to create a new file in `data/conf/postfix/mailcow_anonymize_headers.pcre` and insert the following:
-
-```
-/^\s*Received:.*Authenticated sender:(.+)/
-    REPLACE Received: from localhost (localhost [127.0.0.1]) (Authenticated sender:$1
-/^\s*User-Agent/        IGNORE
-/^\s*X-Enigmail/        IGNORE
-/^\s*X-Mailer/          IGNORE
-/^\s*X-Originating-IP/  IGNORE
-/^\s*X-Forward/         IGNORE
-```
-
-Next we need to add the following to `data/conf/postfix/main.cf`:
-
-```
-smtp_header_checks = pcre:/opt/postfix/conf/mailcow_anonymize_headers.pcre
-```
-
-Then restart Postfix:
-
-```
-docker exec -it $(docker ps -qf name=postfix-mailcow) postfix reload
-```