A.Source interface where encrypted traffic originatesB.……

单项选择题WhichstatementistrueaboutaSmurfattack？（）

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

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