Refertotheexhibit.Inthisnetwork，R1isconfigurednottoperf……

单项选择题Refer to the exhibit. In this network， R1 has been configured to advertise a summary route， 192.168.0.0 22， to R2. R2 has been configured to advertise a summary route， 192.168.0.0 21， to R1. Both routers have been configured to remove the discard route （the route to null created when a summary route is configured） by setting the administrative distance of the discard route to 255. What will happen if R1 receives a packet destined to 192.168.3.1？（）

A. The packet will loop between R1 and R2.
B. It is not possible to set the administrative distance on a summary to 255.
C. The packet will be forwarded to R2， where it will be routed to null0.
D. The packet will be dropped by R1， since there is no route to 192.168.3.1.

单项选择题YouarethenetworkadministratorofasmallLayer2networkwith50users.Lately，usershavebeencomplainingthatthenetworkisveryslow.Whiletroubleshooting，younoticethattheCAMtableofyourswitchisfull，althoughitsupportsupto12，000MACaddresses.Howcanyousolvethisissueandpreventitfromhappeninginthefuture？（）

A.Upgrade the switches
B.Configure BPDU guard
C.Configure VLAN access lists
D.Configure port security
E.Configure Dynamic ARP inspection

单项选择题TworoutersconfiguredtorunBGPhavebeenconnectedtoafirewall，oneontheinsideinterfaceandoneontheoutsideinterface.BGPhasbeenconfiguredsothetworoutersshouldpeer，includingthecorrectBGPsessionendpointaddressesandthecorrectBGPsessionhop-countlimit（EBGPmultihop）.WhatisagoodfirsttesttoseeifBGPwillworkacrossthefirewall？（）

A. Attempt to TELNET from the router connected to the inside of the firewall to the router connected to the outside of the firewall. If telnet works， BGP will work， since telnet and BGP both use TCP to transport data.
B. Ping from the router connected to the inside interface of the firewall to the router connected to the outside interface of the firewall. If you can ping between them， BGP should work， since BGP uses IP to transport packets.
C. There is no way to make BGP work across a firewall without special configuration， so there is no simple test that will show you if BGP will work or not， other than trying to start the peering session.
D. There is no way to make BGP work across a firewall.

多项选择题Youarethenetworkadministratorofamedium-sizedcompany，andusersarecomplainingthattheycannotsendemailstosomeorganizations.Duringyourtroubleshooting，younoticethatyourDNSMXrecordisblacklistedbyseveralpublicblacklistfilters.AfterclearingtheselistingsforyourIPaddress，andassumingthatyouremailserverhastherightvirusprotectioninplace，whataretwopossiblesolutionstopreventthisfromhappeninginthefuture？（）

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.

单项选择题Whiledeployinganewswitch，youaccidentlyconnectports3 12and3 18together，creatingaloop.STPdetecteditandplacedport3 18inblockingmode.WhydidSTPnotplaceport3 12inblockingmodeinstead？（）

A. Port 3/12 was already up and forwarding before the loop was created.
B. Port priority is based on lowest priority and lowest port number.
C. You connected the wire on port 3/18 last.
D. None of the above， it is purely random.