It is quite straightforward to add in additional DBLs to block incoming email with certian characteristics. There are many DBL services available, both free to use and commercial - see here
Here are two example uses:
Blocking on country of origin
First - make sure you are actually using the DBL system as currently
recommended - see the Tutorial here: www.mailtraq.com/dbl
If that hasn't done it for you then you can add additional DBLs for
specific characteristics, such as Afghanistan in this example.
This type of switching is done by country, not language.
A Google search of: dns blacklists will yield a number.
One well known one is http://countries.nerd.dk/ (which seems to work
fine, and is free) and there are commercial offerings as well,
such as www.sbg-rbl.org/
We do not make a particular recommendation.
Getting additional reporting
Some DBL services provide you with additional feedback about the reason for classifying an item as spam
This example uses the old Osirusoft service was one which enabled you to configure the Response Handling and Interpreting Window as follows - but the principle remains the same which ever service you use. Note: Osirusoft is now offline due to a DoS attack.
In the Response Handling and Interpreting Window enter the following, one line at a time
Response=127.0.0.2,Points=101,Message=Blocked as Relay,Header= 127.0.0.2 Blocked as Relay
Response=127.0.0.3,Points=101,Message=Blocked as Dialup,Header= 127.0.0.3 Blocked as Dialup
Response=127.0.0.4,Points=101,Message=Blocked as Manual Entry,Header= 127.0.0.4 Blocked as Manual Entry
Response=127.0.0.5,Points=101,Message=Blocked as Smarthost,Header= 127.0.0.5 Blocked as Smarthost
Response=127.0.0.6,Points=101,Message=Blocked as Spamware,Header=127.0.0.6 Blocked as Spamware
Response=127.0.0.7,Points=101,Message=Blocked as List server,Header= 127.0.0.7 Blocked as List server
Response=127.0.0.8,Points=101,Message=Blocked as Formail,Header= 127.0.0.8 Blocked as Formail
Response=127.0.0.9,Points=101,Message=Blocked as Proxy,Header= 127.0.0.9 Blocked as Proxy
Then click 'OK', back to the Console. Make sure that the 'Enable DBL verification' check box has a check-mark for the DBL server(s) being used.
From now on, Mailtraq will look up the ip address of every connecting smtp client at osirusoft and accept messages if there's no entry and reroute messages to 'spam' if 127.0.0.1 - 127.0.0.9 is returned. You can then examine the messages there on a regular basis and use the information provided by the 'Message' and 'Header' reports to refine your anti-spam rules.
Messages are rerouted when their 'points score' is greater than 100. This means that if any of the reasons for blocking mail are true the message will be rerouted. You may find that you want to accept mail from certain sources that others might consider doubtful.
If you were to change the entry above from
Response=127.0.0.3,Points=101,Message=Blocked as Dialup,Header= 127.0.0.3 Blocked as Dialup
to
Response=127.0.0.3,Points=0,Message=Blocked as Dialup,Header= 127.0.0.3 Blocked as Dialup
then mail from all Dialups on Osirusoft's database will be accepted.
If you change the points in each entry to Points=51 then messages will be rerouted if any two database entries are matched (51+51=102, and Messages are rerouted when their 'points score' is greater than 100), and so on.
You can construct your own rules in a similar way.
If you use more than one dbl source, then you will find it helpful for diagnostic purposes to change the Message and Header entry information to reflect which dbl is causing mail to be re-routed.
For example:
Response=127.0.0.2,Points=101,Message=Blocked as Relay,Header= 127.0.0.2 Blocked as Relay
would be changed to
Response=127.0.0.2,Points=101,Message=Blocked as Relay (Osirusoft),Header= 127.0.0.2 Blocked as Relay (Osirusoft)