Re: [Exim] How unique are exim queue msg IDs?

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Author: Philip Hazel
Date:  
To: Jeffrey Goldberg
CC: The Flying Hamster, exim-users
Subject: Re: [Exim] How unique are exim queue msg IDs?
On Fri, 3 Nov 2000, Jeffrey Goldberg wrote:

> The ID that exim adds will be unique if
>     (a) You never set your machines clock back in time
>     (b) You do not have two instances of exim running on the same host.
>     (c) You aren't running on exim on multiple hosts which think that
>         they have the same name.


(b) Is not relevant. Two instances of Exim will be running in two
different processes. Therefore they will use different process numbers
in the Exim ID. In fact, if your machine is receiving two messages
simultaneously (not uncommon!) there *will* be two instances of Exim
running (as you said).

(c) Is true if we are talking about the Message-ID: header line, added
by Exim, but only in the default case. If you have a set of Exim hosts
and you want Exim's message ids to be unique over the set, you can set
localhost_number.

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.