outgoing_mail_header_filters use local hostname and ip

Modify outgoing_mail_header_filters and mail-postfix.sh
files to result in the primary hostname, and the public
ip of the server showing in the first mail header route
instead of unknown and 127.0.0.1.  This could help lower
the spam score of mail sent from your server to some
public mail services.

conf/postfix_outgoing_mail_header_filters

@@ -1,7 +1,7 @@
 # Remove the first line of the Received: header. Note that we cannot fully remove the Received: header
 # because OpenDKIM requires that a header be present when signing outbound mail. The first line is
 # where the user's home IP address would be.
-/^\s*Received:[^\n]*(.*)/         REPLACE Received: from authenticated-user (unknown [127.0.0.1])$1
+/^\s*Received:[^\n]*(.*)/         REPLACE Received: from authenticated-user (PRIMARY_HOSTNAME [PUBLIC_IP])$1
 
 # Remove other typically private information.
 /^\s*User-Agent:/        IGNORE

setup/mail-postfix.sh

@@ -93,6 +93,12 @@ tools/editconf.py /etc/postfix/master.cf -s -w \
 # Install the `outgoing_mail_header_filters` file required by the new 'authclean' service.
 cp conf/postfix_outgoing_mail_header_filters /etc/postfix/outgoing_mail_header_filters
 
+# Modify the `outgoing_mail_header_filters` file to use the local machine name and ip 
+# on the first received header line.  This may help reduce the spam score of email by
+# removing the 127.0.0.1 reference.
+sed -i "s/PRIMARY_HOSTNAME/$PRIMARY_HOSTNAME/" /etc/postfix/outgoing_mail_header_filters
+sed -i "s/PUBLIC_IP/$PUBLIC_IP/" /etc/postfix/outgoing_mail_header_filters
+
 # Enable TLS on these and all other connections (i.e. ports 25 *and* 587) and
 # require TLS before a user is allowed to authenticate. This also makes
 # opportunistic TLS available on *incoming* mail.