Re: [exim] How do I disable double at sign in message-ID?

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Autor: Mike Brudenell
Data:  
Dla: exim-users@exim.org
Temat: Re: [exim] How do I disable double at sign in message-ID?
Hi,

On 30 May 2017 at 13:32, Imri Paloja || De Hosting Makelaar <
Imri@???> wrote:

> Pardon me asking, but I see the double at sign in the mail log on our
> server, meaning the double at sign is created by EXIM?
>
> How does one disable the double at sign in EXIM?
>


Every email message should have a "Message-ID" header that includes a value
that uniquely identifies the message. It looks a bit like an email address.

Usually the software that creates the message should generate and add the
Message-ID header to it. The mail servers it passes through then log the
message along with its Message-ID to assist with tracing.

However if a message arrives at a mail server without a Message-ID header
then the mail server software itself usually generates one and adds it to
the the message. Later mail servers will then see and log that.

So you need to try and work out what is generating the strange Message-ID
that contains two "@" characters…

Start by looking in your Exim logfiles for the entry that shows the message
*arriving* into your mail server system. This log line will include a " <=
" marker to show its about the message arriving on your system. Does this
log line include an attribute named "id"? For example, something like

… id=*something*@*somethingelse* …


If this is present then it means that there was a Message-ID header already
present in the message your Exim was receiving: that your Exim *did
not* generate
the Message-ID value, but instead some mail software further upstream
produced it.

If there is no "id=" attribute logged on the arrival line then Exim didn't
find a Message-ID header within the incoming message so had to create one
itself. However when it does so it generates a value that has a very
specific format:

*Exxxxxx-xxxxx-xx*@*your.computer.name <http://your.computer.name>*


That is, it

- begins with the letter "E"
- is followed by the internal id string Exim uses to track your message
whilst processing it (the "*xxxxx-xxxx-xx*" part of the example above)
- has the full hostname of the computer Exim is running on after the
"@" (the "*your.computer.name <http://your.computer.name>*" part of the
example above)

The example Message-ID value you gave isn't of this form, which indicates
your Exim didn't generate/add the strange Message-ID.

That's why I think you'll find an "id=" attribute on the "<=" log line
showing your message's arrival into Exim, which will confirm that you need
to look further back at the thing that sent you the email: the problem lies
updstream, either at the software which generated the message, or (if there
are any) in one of the mail servers it flowed through on its way to your
Exim.

Cheers,
Mike B-)

--
Systems Administrator & Change Manager
IT Services, University of York, Heslington, York YO10 5DD, UK
Tel: +44-(0)1904-323811

Web: www.york.ac.uk/it-services
Disclaimer: www.york.ac.uk/docs/disclaimer/email.htm