单项选择题

Which statement is true about a Smurf attack？（）

A.It sends ping requests in segments of an invalid size
B.It intercepts the third step in a TCP three-way handshake to hijack a session
C.It sends ping requests to a subnet， requesting that devices on that subnet send ping replies to a targetsystem
D.It uses Trojan horse applications to create a distributed collection of "zombie" computers， which can beused to launch a coordinated DDoS attack

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热门试题

单项选择题Whatwillbedisabledasaresultofthenoservicepassword-recoverycommand？（）

A.password encryption service
B.changes to the config-register setting
C.the xmodem privilege EXEC mode command to recover the Cisco IOS image
D.ROMMON

单项选择题AstandardaccesscontrollisthasbeenconfiguredonarouterandappliedtointerfaceSerial0inanoutbounddirection.NoACLisappliedtoInterfaceSerial1onthesamerouter.WhatwillhappenwhentrafficbeingfilteredbytheaccesslistdoesnotmatchtheconfiguredACLstatementsforSerial0？（）

A.The traffic is dropped
B.The resulting action is determined by the destination IP address
C.The source IP address is checked，and，if a match is not found， traffic is routed out interface Serial 1
D.The resulting action is determined by the destination IP address and port number

单项选择题Regardingconstructingagoodencryptionalgorithm，whatdoescreatinganavalancheeffectindicate？（）

A.Altering the key length causes the ciphertext to be completely different
B.Changing only a few bits of a ciphertext message causes the plain text to be completely different
C.Altering the key length causes the plain text to be completely different
D.Changing only a few bits of a plain-text message causes the ciphertext to be completely different

单项选择题WhichitemiscorrectregardingCiscoIOSIPSonCiscoIOSRelease12.4（11）Tandlater？（）

A.requires the Basic or Advanced Signature Definition File
B.uses the built-in signatures that come with the Cisco IOS image as backup
C.supports SDEE，SYSLOG，and SNMP for sending Cisco IPS alerts
D.uses Cisco IPS 5.x signature format

单项选择题AfterenablingportsecurityonaCiscoCatalystswitch，whatisthedefaultactionwhentheconfiguredmaximumofallowedMACaddressesvalueisexceeded？（）

A.The port’s violation mode is set to restrict
B.The port is shut down
C.The MAC address table is cleared and the new MAC address is entered into the table
D.The port remains enabled， but bandwidth is throttled until old MAC addresses are aged out