Actually i did something like this :
for (( i=1 ; i<=255 ; ++i )) ; do echo iroute $i.0.0.0 255.0.0.0 >> ccd-file;done;
Paying attention to add into the server.conf the following directive :
max-routes-per-client 50000
Right now is catching every ip i try to reach, althought is not a "clean solution" :cry:
