ARP协议的作用是（18）。
A.由MAC地址求lP地址
B.由IP地址求MAC地址
C.由lP地址查域名
D.由域名查IP地址

（）是工作在客户/服务器（C/S）模式下且基于TCP协议。
A.DHCP
B.HTTP
C.SNMP
D.DNS

RSA是一种（）算法。
A.共享密钥
B.公开密钥
C.报文摘要
D.访问控制

通过Samba组件实现Linux与Windows文件资源共享时，需要提供的守护进程（daemon）是（ ）。
A.bind
B.smbd
C.named
D.shard

以下关于入侵检测系统的描述中，正确的是（）
A.实现内外网隔离与访问控制
B.对进出网络的信息进行实时的监测与比对，及时发现攻击行为
C.隐藏内部网络拓扑
D.预防、检测和消除网络病毒

The TTL field was originally designed to hold a time stamp, which was decremented by each visited router. The datagram was （ ） when the value became zero. However, for this scheme, all the machines must have synchronized clocks and must know how long it takes for a datagram to go from one machine to another. Today, this field is used mostly to control the （ ） number of hops （routers） visited by the datagram. When a source host sends the datagram, it （请作答此空） a number in this field. Each router that processes the datagram decrements this number by 1. If this value, after being decremented, is zero, the router discards the datagram.This field is needed because routing tables in the Internet can become corrupted.A datagram may travel between two or more routers for a long time without ever getting delivered to the （ ）.This field limits the （ ） of a datagram.
Acontrols
Btransmits
Cstores
Dreceives