[exim] local_from_check=false not working?

I am having a problem with Exim rewriting the "To:" and "From:" headers
in messages that are locally generated. If either of these two headers
is missing a domain name then Exim is inserting the domain declared by
"qualify_domain". I tried undefining "qualify_domain" but Exim used the
value of "primary_hostname" instead.

We are a spam filtering service provider. When spammers do not provide
valid data in their headers Exim is supplementing those headers with our
own domain name. This is interpreted in various ways by our customers,
none of them being very complementary to us.

According to the spec the main configuration option
"local_from_check=false" can disable this for the "From:" header, but A)
it isn't, and B) there is no "local_to_check=false" option. Though I
did look at the "local_sender_retain" option I discarded it as I am not
concerned with the "Sender:" header at this time (I tried it anyway with
no visible effect).

Below is a relevant sample from a command line invocation run as root
(one of the "trusted_users"). In my configs
"qualify_domain=puremail.com" and "local_from_check=false". In this
sample both the sender and recipient headers do not contain domain
names. As evident by the output below I am running Exim version 4.30.

Have I misunderstood the intention of the "local_to_check=false"
option? How do I achieve the same desired result (not modifying the
header at all) for the "To:" header?

Thanks in advance. - John R. S.


<<<<< Begin Sample Transaction >>>>>

# exim -d -v -f nobody@??? test1@??? << EoD
> From: "Joe D. Spammer"
> To: "Unlucky M. Alebox"
> Subject: Failure of local_from_check=no
>
> This is a sample message
> EoD
Exim version 4.30 uid=0 gid=0 pid=9396 D=fbb95cfd
Berkeley DB: Sleepycat Software: Berkeley DB 2.7.7: (08/20/99)
Support for: iconv()
Lookups: lsearch wildlsearch nwildlsearch dbm dmbnz dsearch passwd
Authenticators:
Routers: accept dnslookup ipliteral iplookup manualroute queryprogram
redirect
Transports: appendfile/maildir autoreply pipe smtp
Fixed never_users: 0
changed uid/gid: forcing real = effective
uid=0 gid=0 pid=9396
auxiliary group list: <none>
configuration file is /etc/exim4/exim4.conf
log selector = 040d99d8
trusted user
admin user
changed uid/gid: privilege not needed
uid=1003 gid=1003 pid=9396
auxiliary group list: <none>
finduser used cached passwd data for www-data
finduser used cached passwd data for www-data
originator: uid=0 gid=0 login=root name=
sender address = nobody@???
set_process_info: 9396 accepting a local non-SMTP message from
<nobody@???>
Sender: nobody@???
Recipients:
test1@???
search_tidyup called
>>Headers received:
From: "Joe D. Spammer"
To: "Unlucky M. Alebox"
Subject: Failure of local_from_check=no

rewrite_one_header: type=F:
From: "Joe D. Spammer"
newlen=36 newtype=F newtext:
From: "Joe D. Spammer"@???
remainder:
rewrite_one_header: type=T:
To: "Unlucky M. Alebox"
newlen=37 newtype=T newtext:
To: "Unlucky M. Alebox"@???
remainder:
search_tidyup called
...

<<<<< End Sample Transaction >>>>>