[Mimedefang] received headers ofuscation

[ulver]

thanks guys!!, following your advices (and googling a lot) i achieve these piece of code (on filter_end)

 $header_object = $entity->head;
 $received_1st = $header_object->get('Received',0);
 md_syslog('info', "Received headers: $received_1st"); #4-debug
 $received_1st =~ s/(\(8\.13\.8\/8\.13\.8\/.*\)|\(Postfix\))//g;#yeah the regexp could be more general
 $received_1st =~ s/\s{2,}/ /g;
 $received_1st =~ s/\n$//g;
 action_change_header('Received', "$received_1st",0);

 with this i'm able to change the very first received header ..but not the rest of the received lines... :S 

if i try with  something such as   (after the first piece of code)

 $received_2nd = $header_object->get('Received',1);
 md_syslog('info', "Received headers: $received_2nd");
 $received_2nd =~ s/(\(8\.13\.8\/8\.13\.8\/.*\)|\(Postfix\))//g;
 $received_2nd =~ s/\s{2,}/ /g;
 $received_2nd =~ s/\n$//g;
 action_change_header('Received', "$received_2nd",1);

 i got an ...nice Slave 0 stderr: Can't use an undefined value as a SCALAR reference at.....

 could someone help me ? or could someone tell me where would i read in order to understand how   $entity->head works?