anchor.diff:  
         recipientDelimiter = ${cfg.recipientDelimiter}
       ''
  +    + optionalString (cfg.virtual != "") ''
  +      virtual_alias_maps = hash:/etc/postfix/virtual
  +    ''
       + cfg.extraConfig;
   
     aliases =
  
positive.code:             ln -sf ${pkgs.postfix}/share/postfix/conf/* /var/postfix/conf
  
              ln -sf ${aliasesFile} /var/postfix/conf/aliases
              ln -sf ${mainCfFile} /var/postfix/conf/main.cf
  
              ${pkgs.postfix}/sbin/postalias -c /var/postfix/conf /var/postfix/conf/aliases
  
              exec ${pkgs.postfix}/sbin/postfix -c /var/postfix/conf start
            ''; # */
  
negative.code:         example = "+";
          description = "
            Delimiter for address extension: so mail to user+test can be handled by ~user/.forward+test
          ";
        };
  
        virtual = mkOption {
          default = "";
          description = "
            Entries for the virtual alias map.
          ";
        };
  
  