Re: FW: [Exim] Unqualified hostnames in To and From fields

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Autor: Edgar Lovecraft
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A: exim-users
Assumpte: Re: FW: [Exim] Unqualified hostnames in To and From fields
Steve Karlsen wrote:
>

..[snip]...
> >
> > I have exim running on a private internal network (was recently
> > sendmail) as a relay, it relays traffic from one node to other a couple
> > of other nodes, nothing special.
> >
> > However, due to the nature of the traffic, I require to accept
> > unqualified hosts in the To and from headers (not the envelope To/From
> > fields) and relay them as is (unqualified) to the next host.
>

Okay, then you 'should' be able to do this just fine as long as the
MAIL FROM: <user@domain> and RCPT TO: <user@domain> is how you accept the
address during the SMTP transaction.
If you accept the commands as MAIL FROM: <user> and RCPT TO: <user> you
are kind of out-a-luck here. follow along and see why :)
>
> > I have set sender_unqualified_hosts and recipient_unqualified_hosts,
> > appropriately,
>

This is either the fixing pint, or the breaking point.
>
> > but I gather, that this just allows them to be accepted,
> > it seems that both headers get locally qualified, as they should do,
>

Possibly...
>
> > but is it possible to turn this off? Have scoured the docs and threads
> > on google, but haven't found a lot.
> > It was possible to turn it off in sendmail.
> >
>

--
Okay, here is the explination...
After double checking the DOCs myself, here is what I found:

one)
recipient_unqualified_hosts
Type: host list, expanded
Default: unset
This option lists those hosts from which Exim is prepared to accept
unqualified recipient addresses in message envelopes. The addresses are
made fully qualified by the addition of the qualify_recipient value. This
option also affects message header lines. Exim does not reject unqualified
recipient addresses in headers, but it qualifies them only if the message
came from a host that matches recipient_unqualified_hosts.

two)
sender_unqualified_hosts
Type: host list, expanded
Default: unset
This option lists those hosts from which Exim is prepared to accept
unqualified sender addresses. The addresses are made fully qualified by the
addition of qualify_domain. This option also affects message header lines.
Exim does not reject unqualified addresses in headers that contain sender
addresses, but it qualifies them only if the message came from a host that
matches sender_unqualified_hosts.

three)
http://www.exim.org/exim-html-4.30/doc/html/spec_31.html#CHAP31

There are some circumstances in which Exim automatically rewrites domains
in addresses. The two most common are when an address is given without a
domain (referred to as an "unqualified address") or when an address
contains an abbreviated domain that is expanded by DNS lookup.
Unqualified envelope addresses are accepted only for locally submitted
messages, or messages from hosts that match sender_unqualified_hosts or
recipient_unqualified_hosts, respectively. Unqualified addresses in header
lines are qualified if they are in locally submitted messages, or messages
from hosts that are permitted to send unqualified envelope addresses.
Otherwise, unqualified addresses in header lines are neither qualified nor
rewritten.

Notice the language that is used, exim only accecpts the MAIL FROM: and
RCPT TO: commands in the 'qualified' way (i.e. RCPT TO: <user@domain>) if
you only accept this way then you should be okay, as the next line states,
'unqualified addresses in header lines are neither qualified nor
rewritten.' now remember this is only true if the connecting host is not in
either of the 'recipient_unqualified_hosts' or 'sender_unqualified_hosts'.

So to try to be absolutley clear here,
remove the nodes from the unqualified settings in the configs, this will
leave the message headers alone. this can only be however, if those nodes
send the SMTP commands in a qualified manner.

Got it? :)

--EAL--