An administrator has provided a 24 bit netmask.  Which of the following options indicates the number of host addresses that are available in a network？（）

单项选择题AclassBnetwork129.35has10subnets.Whichofthefollowingoptionsisthecorrectsubnetmask？（）

A.255.255.128.0 （11111111.11111111.10000000.00000000）
B.255.255.192.0 （11111111.11111111.11000000.00000000）
C.255.255.224.0 （11111111.11111111.11100000.00000000）
D.255.255.240.0 （11111111.11111111.11110000.00000000）

单项选择题ADNSserverforalargenetworkisexperiencingperformanceproblems.Whichofthefollowingoptionsisthebestsolutiontofixtheproblem？（）

A.Enable NIS
B.Purchase a larger server
C.Use /etc/hosts on all of the systems
D.Create secondary name servers throughout the network

单项选择题AnIPaddressis198.37.16.23.Whichofthefollowingrouter’sIPaddressesshouldbeusedtoroutetraffictothe193.130.56.0network？（）

A.193.130.56.0
B.198.37.16.15
C.198.130.16.15
D.198.130.56.15

单项选择题Ahostisexpectedtobeamailrelayorreceivingendpoint.Whichofthefollowingdaemonsshouldbelisteningforconnectionsonport25？（）

A.ftpd
B.imapd
C.pop3d
D.sendmail

单项选择题Amachine’sONLYexternalinterfaceisconfiguredwithanaddressof192.168.5.1andanetmaskof255.255.255.0.Noslotsareavailableforexpansion.Whichofthefollowingproceduresshouldbeperformedtomakeitfunctionasagateway？（）

A.Enable ipforwarding only
B.Configure an alias on the same interface and enable ipforwarding
C.Add a second interface into the same subnet and enable ipforwarding
D.Add a second interface into a different subnet， and enable ipforwarding