Merge #1871

1871: Replace PUBLIC_HOSTNAME/IP with real data in Received headers r=mergify[bot] a=nextgens

## What type of PR?

bug-fix

## What does this PR do?

This will ensure that we don't get spam points for not respecting the RFC (gmail is notorious for not liking it)

### Related issue(s)
- close #1448
- #466
- #191

## Prerequistes
Before we can consider review and merge, please make sure the following list is done and checked.
If an entry in not applicable, you can check it or remove it from the list.

- [x] In case of feature or enhancement: documentation updated accordingly
- [x] Unless it's docs or a minor change: add [changelog](https://mailu.io/master/contributors/workflow.html#changelog) entry file.


Co-authored-by: Florent Daigniere <nextgens@freenetproject.org>

core/postfix/conf/outclean_header_filter.cf

@@ -4,7 +4,7 @@
 # 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 (PRIMARY_HOSTNAME [PUBLIC_IP])$1
+/^\s*Received:[^\n]*(.*)/         REPLACE Received: from authenticated-user ({{OUTCLEAN}} [{{OUTCLEAN_ADDRESS}}])$1
 
 # Remove other typically private information.
 /^\s*User-Agent:/        IGNORE

core/postfix/start.py

@@ -36,6 +36,11 @@ os.environ["FRONT_ADDRESS"] = system.get_host_address_from_environment("FRONT",
 os.environ["ADMIN_ADDRESS"] = system.get_host_address_from_environment("ADMIN", "admin")
 os.environ["ANTISPAM_MILTER_ADDRESS"] = system.get_host_address_from_environment("ANTISPAM_MILTER", "antispam:11332")
 os.environ["LMTP_ADDRESS"] = system.get_host_address_from_environment("LMTP", "imap:2525")
+os.environ["OUTCLEAN"] = os.environ["HOSTNAMES"].split(",")[0]
+try:
+    os.environ["OUTCLEAN_ADDRESS"] = system.resolve_hostname(os.environ["OUTCLEAN"])
+except:
+    os.environ["OUTCLEAN_ADDRESS"] = "10.10.10.10"
 
 for postfix_file in glob.glob("/conf/*.cf"):
     conf.jinja(postfix_file, os.environ, os.path.join("/etc/postfix", os.path.basename(postfix_file)))

towncrier/newsfragments/191.bugfix

@@ -0,0 +1 @@
+Replace PUBLIC_HOSTNAME and PUBLIC_IP in "Received" headers to ensure that no undue spam points are attributed