Cookie为客户端持久保持数据提供了方便，但也存在一定的弊端。下列选项中，不属于Cookie弊端的是（ ）。
Cookie作用如下：
（1）可以在客户端上保存用户数据，起到简单的缓存和用户身份识别等作用。
（2）保存用户的登录状态，用户进行登陆，成功登陆后，服务器生成特定的Cookie返回给客户端，客户端下次访问该域名下的任何页面，将该Cookie的信息发送给服务器，服务器经过检验，来判断用户是否登陆。
（3）记录用户的行为。
（4）通过加密和安全传输技术（SSL），减少Cookie被破解的可能性。只在Cookie中存放不敏感数据，即使被盗也不会有重大损失。控制Cookie的生命期，使之不会永远有效。偷盗者很可能拿到一个过期的Cookie。
Cookie弊端：
（1）增加流量消耗，每次请求都需要带上Cookie信息。
（2）安全性隐患，Cookie使用明文传输。如果Cookie被人拦截了，那人就可以取得所有的session信息。
（3）Cookie数量和长度的限制。每个domain最多只能有20条Cookie，每个Cookie长度不能超过4kB，否则会被截掉。D项。保存访问站点的缓存数据是Cookie的作用，而不是Cookie的弊端。
Unified Modeling Language（UML） is a widely used method of visualizing and documenting an information system. The UML can be used to develop（ 71 ）, in which an object represents a person, place, event, or transaction that is significant to the information system. Systems analysts define an object's attributes during the（ 72 ）. An object also has（ 73 ）which are tasks or functions that the object performs when it receives a message, or command, to do so. A（n）（ 74 ）is a group of similar objects. If objects are similar to nouns, attributes are similar to adjectives that describe the characteristics of an object. Objects can have a specific attribute called a（n）（ 75 ）, which of an object is an adjective that describes the object's current status. All objects within a class share common attributes and methods, so a class is like a blueprint, or template for all the objects within the class.
Unified Modeling Language（UML） is a widely used method of visualizing and documenting an information system. The UML can be used to develop（ 71 ）, in which an object represents a person, place, event, or transaction that is significant to the information system. Systems analysts define an object's attributes during the（ 72 ）. An object also has（ 73 ）which are tasks or functions that the object performs when it receives a message, or command, to do so. A（n）（ 74 ）is a group of similar objects. If objects are similar to nouns, attributes are similar to adjectives that describe the characteristics of an object. Objects can have a specific attribute called a（n）（ 75 ）, which of an object is an adjective that describes the object's current status. All objects within a class share common attributes and methods, so a class is like a blueprint, or template for all the objects within the class.
Unified Modeling Language（UML） is a widely used method of visualizing and documenting an information system. The UML can be used to develop（ 71 ）, in which an object represents a person, place, event, or transaction that is significant to the information system. Systems analysts define an object's attributes during the（ 72 ）. An object also has（ 73 ）which are tasks or functions that the object performs when it receives a message, or command, to do so. A（n）（ 74 ）is a group of similar objects. If objects are similar to nouns, attributes are similar to adjectives that describe the characteristics of an object. Objects can have a specific attribute called a（n）（ 75 ）, which of an object is an adjective that describes the object's current status. All objects within a class share common attributes and methods, so a class is like a blueprint, or template for all the objects within the class.
Unified Modeling Language（UML） is a widely used method of visualizing and documenting an information system. The UML can be used to develop（ 71 ）, in which an object represents a person, place, event, or transaction that is significant to the information system. Systems analysts define an object's attributes during the（ 72 ）. An object also has（ 73 ）which are tasks or functions that the object performs when it receives a message, or command, to do so. A（n）（ 74 ）is a group of similar objects. If objects are similar to nouns, attributes are similar to adjectives that describe the characteristics of an object. Objects can have a specific attribute called a（n）（ 75 ）, which of an object is an adjective that describes the object's current status. All objects within a class share common attributes and methods, so a class is like a blueprint, or template for all the objects within the class.
Unified Modeling Language（UML） is a widely used method of visualizing and documenting an information system. The UML can be used to develop（ 71 ）, in which an object represents a person, place, event, or transaction that is significant to the information system. Systems analysts define an object's attributes during the（ 72 ）. An object also has（ 73 ）which are tasks or functions that the object performs when it receives a message, or command, to do so. A（n）（ 74 ）is a group of similar objects. If objects are similar to nouns, attributes are similar to adjectives that describe the characteristics of an object. Objects can have a specific attribute called a（n）（ 75 ）, which of an object is an adjective that describes the object's current status. All objects within a class share common attributes and methods, so a class is like a blueprint, or template for all the objects within the class.
为了控制IP报文在网络中无限转发，在IPv4数据报首部中设置了（ ）字段。
在Linux系统中，DNS配置文件的（ ）参数，用于确定DNS服务器地址。
用户在登录FTP服务器的过程中，建立TCP连接时使用的默认端口号是（ ）。
使用电子邮件客户端从服务器下载邮件，能实现邮件的移动、删除等操作在客户端和邮箱上更新同步，所使用的电子邮件接收协议是（ ）。
Cookie为客户端持久保持数据提供了方便，但也存在一定的弊端。下列选项中，不属于Cookie弊端的是（ ）。
