non-existent msgids & duplicate delivery suppression

Phil Chambers P.A.Chambers at
Fri Jun 27 12:59:35 EDT 2003

On Fri, 27 Jun 2003 16:52:02 +0100 (BST) David Carter <dpc22 at> wrote:

> On Fri, 27 Jun 2003, Stephen Grier wrote:
> > We use Exim here. The messages do have a Message-Id: header, but with an
> > empty value.
> Eeep. That's no fun at all.
> > I assume Exim will not add or alter the msg-id in this case.
> I suspect this is the case, though arguably Exim should do something about
> this case. I'll have a chat with Philip the next time that I see him.

Exim can be made to replace a blank message-id with a good one.  Alternatively, if 
you switch on strict header testing it should reject the message because a blank 
message-id does not conform to the header syntax.

Replacing the header will depend on the version of exim.  With exim-4, in the 
relevant transport you could have a headers_remove line which is conditional on the 
message-id being blank, then have a headers_add line, similarly conditional.

I am not an expert, but a message to exim-users at should give a detailed 
solution (be sure to say what version of exim you have: "exim -bV" will give it).

Phil Chambers (postmaster at
University of Exeter

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