sobre exim y estructura de fichero cdb

[Felix Vladimir Roldan Jimenez <vladimir@fie.uo.edu.cu>]

saludos
quiero hacer un reescritura de direcciones en exim
y en el man encontré esto:

This example uses the int_smtp transport for domains ending in 
.my.domain, and ext_smtp for everything else. The ext_smtp transport 
could be something like this:
  ext_smtp:
    driver = smtp
    headers_rewrite = *@*.my.domain \
         ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}
    return_path = \
      ${if match{$return_path}{\N^([^@]+)@(.*)\.my\.domain$\N}\
       {\
       ${lookup{$1}cdb{/etc/$2/mail.handles.cdb}{$value}fail}\
       }\
       fail}
This example uses a separate file of local-to-external address 
translations for each domain. This is not the only possibility, of 
course. The headers_rewrite and return_path options apply the same 
rewriting to the header lines and the envelope sender address, respectively.

Entonces mi pregunta es el fichero mail.handles.cdb que estructura tendría

--
************************************
ING. Félix Vladimir Roldán Jiménez  
.Universidad de Oriente
.Facultad de Ing. Eléctrica
.Departamento de Control Automático 
.Usuario Linux # 352492
.www.uo.edu.cu
************************************