This short document shows how to modify your exim configuration to integrate dspam domainwide.

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These settings add a router to report to dspam undetected spam by sending the spam as attachment to spam-loginname@yourdomain.tld

.ifdef DSPAM_ENABLED
dspam_addspam:  
        local_part_prefix = spam-
        driver          = accept
        transport       = addspam

dspam_falsepositive:  
        local_part_prefix = falsepos-
        driver          = accept
        transport       = falsepositive
.endif

Let's do the same for the transports

.ifdef DSPAM_ENABLED
addspam:
        driver          = pipe
        command         = /usr/local/bin/dspam --user $local_part --class=spam --source=error
        user            = _dspam
        return_path_add = false
        return_fail_output = true
        log_output      = true
        home_directory  = "/tmp"
        current_directory = "/tmp"


falsepositive:  
        driver          = pipe  
        command         = /usr/local/bin/dspam --user $local_part --class=innocent --source=error --deliver=innocent %u
        user            = _dspam
        return_path_add = false  
        return_fail_output = true  
        log_output      = true  
        home_directory  = "/tmp"  
        current_directory = "/tmp"  
.endif

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Now the little rule that makes you use no additional transport for scanning mails through dspam

maildir_home:
        debug_print     = "T: maildir_home for $local_part@$domain"
        driver          = appendfile
        directory       = $home/Maildir
.ifdef DSPAM_ENABLED
        transport_filter = /usr/local/bin/dspam -oMr dspam-verified --deliver=innocent --client --feature=ch,no,whitelist --stdout
.endif
        delivery_date_add
        envelope_to_add
        return_path_add
        maildir_format
        mode            = 0600
        mode_fail_narrower = false



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Dspam was compiled with the following options:
./configure --sysconfdir="/etc/dspam" --disable-mysql4-initialization --with-dspam-home=/var/dspam/ \
	--with-mysql-libraries=/usr/local/mysql5/lib/mysql/lib \
	--with-mysql-includes=/usr/local/mysql5/include/mysql/ --with-storage-driver=mysql_drv \
	--with-delivery-agent="/usr/local/exim/exim" --enable-daemon --enable-domain-scale \
	--with-dspam-home-owner=_dspam --enable-virtual-users --with-dspam-home-group=_dspam \
	--enable-neural-networking

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In dspam.conf, I would advise to enable dspam signature only in headers with the following line:
Preference "signatureLocation=headers"
This helps preserve the original mail presentation.