As ZMailer internal id's are purely based on the inode number of the message
file, these id's are, by no means, unique... what's more, in linux, they
repeat frequently... sometimes within the same second (that is, when the
beast is running fast)...

So when I started adding log entries to a SQL database (in a different way of
the standard SQLLogging, but with many ideas borrowed from it) I found myself
trying to find a suitable Id for joining the tables.

The easiest thing to do is to generate a serial entry in the message table
and use it in the recipient & report tables, but then I also wanted the Id to
be in the message itself, so I can cross reference between the database and
the messages themselves.

So off I went... and modified MailScanner to do this... I generated an Id
based on the hostname, process-id, timestamp, originating IP (clientip), from
and to list... it seems to be quite unique... otherwise, we could add some
randomness to it...

I thought about leaving the text form just "as is"... but it was really too
long to use it as an effective id in 3 different tables. So I did an MD5
checksum and stored that... but later I missed the verbosity of the text
form, so I let the header with both forms, first the checksum, and then (in a
new line that starts with a tab, RFC2822-compliant) the long form...

The following files had to be modified for this to work:
/opt/bin/MailScanner
/opt/lib/MailScanner.pm
/opt/lib/MailScanner/ConfigDefs.pl
/opt/lib/MailScanner/Message.pm

I let a set of complete modified files (as well as individual patches for
4.24-4) in http://www.baby.com.ar/MailScanner/id-patch/

Please, let me know what you think.

Oh... you have to add the following lines to MailScanner.conf to make it
work:

Id Header = X-MailScanner-%org-name%-Id:
Include Id Header = yes

by default, the header will not be added.

============================================================================
I was a bit uneasy about the uniqness of the id, so, before md5-digesting it, 
I added the MTA-level id ($message->{id}) and a little bit of random 
(int(rand(1_000_000))) to it.

OTOH, the fact that the X-MailScanner-Id was showing the md5 string _AND_ the 
original string poses some information disclosure, since it is showing all of 
the recipients of a message to all the recipients, and that might include one 
or more "blind" recipients ("Bcc:")... so now, if you say (in the 
MailScanner.conf file):

Include Id Header = yes
Full Id Header = no

it will _only_ show the md5 string... if you want both, you have to say:

Include Id Header = yes
Full Id Header = yes

The default for both options is "no".
=============================================================================
The easiest way to apply the patch is to use the complete patch in
MS-4.24-4-id.patch

cd /opt
patch -p0 < MS-4.24-4-id.patch

and off you go.