多项选择题

Youarethenetworkadministratorofamedium-sizedcompany，and……

You are the network administrator of a medium-sized company， and users are complaining that they cannot send emails to some organizations. During your troubleshooting， you notice that your DNS MX record is blacklisted by several public blacklist filters. After clearing these listings for your IP address， and assuming that your email server has the right virus protection in place， what are two possible solutions to prevent this from happening in the future？（）

A.Change your Internet provider.
B.Change your public IP address.
C.Allow the email server to send traffic only to TCP port 25.
D.Put your email server in a DMZ.
E.Use a separate public IP address for your email server only.

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单项选择题AfterapplyinganewACLonadevice，itsCPUutilizationrosesignificantlyandmanymessagesstartingwith %SEC-6-IPACCESSLOG appearedontheSyslogserver.Whatcanbedonetoresolvethissituation？（）

A.Increase memory allocation for ACLs.
B.Remove all entries from the ACL and use a single permit ip any any statement.
C.Remove the log keyword from each ACL entry.
D.Reboot the device after the ACL has been applied.

单项选择题WhichfeaturewouldpreventguestusersfromgainingnetworkaccessbyunplugginganIPphoneandconnectingalaptopcomputer？（）

A.IPSec VPN
B.SSL VPN
C.port security
D.port security with statically configured MAC addresses
E.private VLANs

多项选择题Yournetworkissufferingfromregularoutages.Aftertroubleshooting，youlearnthatthetransmitleadofafiberuplinkwasdamaged.Whichtwofeaturescanpreventthesameissuesinthefuture？（）

A.root guard
B.loop guard
C.BPDU guard
D.UDLD
E.BPDU skew detection

单项选择题Whileyouaretroubleshootingnetworkperformanceissues，younoticethataswitchisperiodicallyfloodingallunicasttraffic.FurtherinvestigationrevealsthatperiodicallytheswitchisalsohavingspikesinCPUutilization，causingtheMACaddresstabletobeflushedandrelearned.Whatisthemostlikelycauseofthisissue？（）

A.a routing protocol that is flooding updates
B.a flapping port that is generating BPDUs with the TCN bit set
C.STP is not running on the switch
D.a user that is downloading the output of the show-tech command
E.a corrupted switch CAM table

单项选择题ForarouterconnectedtotwoISPsforredundancy，usingIPSLAandstaticrouting，howwouldyouconfigureuRPFontheuplinkinterface？（）

A.ip verify unicast source reachable-via any
B.ip verify unicast reverse-path
C.ip verify unicast reverse-path loose
D.ip verify unicast reverse-path strict