diff --git a/postfix/conf/master.cf b/postfix/conf/master.cf
index 47cb4af6..d8c88379 100644
--- a/postfix/conf/master.cf
+++ b/postfix/conf/master.cf
@@ -7,7 +7,7 @@ smtp      inet  n       -       n       -       -       smtpd
 
 # Additional services
 outclean   unix n       -       n       -       0       cleanup
-  -o header_checks=pcre:/etc/postfix/outclean_header_filter
+  -o header_checks=pcre:/etc/postfix/outclean_header_filter.cf
 
 # Internal postfix services
 pickup    unix  n       -       n       60      1       pickup
diff --git a/postfix/conf/outclean_header_filter b/postfix/conf/outclean_header_filter.cf
similarity index 100%
rename from postfix/conf/outclean_header_filter
rename to postfix/conf/outclean_header_filter.cf