anchor.diff:          default = "";
           description = "
             Entries for the virtual alias map, cf. man-page virtual(8).
  +        ";
  +      };
  +
  +      transport = mkOption {
  +        default = "";
  +        description = "
  +          Entries for the transport map, cf. man-page transport(8).
           ";
         };
   
  
positive.code:   virtualFile = pkgs.writeText "postfix-virtual" cfg.virtual;
    mainCfFile = pkgs.writeText "postfix-main.cf" mainCf;
    masterCfFile = pkgs.writeText "postfix-master.cf" masterCf;
  
  in
  
  
negative.code:           ln -sf ${virtualFile} /var/postfix/conf/virtual
            ln -sf ${mainCfFile} /var/postfix/conf/main.cf
            ln -sf ${masterCfFile} /var/postfix/conf/master.cf
            ln -sf ${transportFile} /var/postfix/conf/transport
  
            ${pkgs.postfix}/sbin/postalias -c /var/postfix/conf /var/postfix/conf/aliases
            ${pkgs.postfix}/sbin/postmap -c /var/postfix/conf /var/postfix/conf/virtual
  