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- CCNA Routing and Switching 200-105
26.
With IEEE 802.1x, which role does a LAN switch typically play?
- A.Authentication server
- B.Supplicant
- C.Translator
- D.Authenticator
- Answer & Explanation
- Report
Answer : [D]
Explanation :
Explanation :
| Of the four answers, the answer "translator" is not an 802.1x role, but the other three are 802.1x roles. The device that is connecting to the network and would like to gain access is the supplicant. The AAA server that can check its list of usernames and passwords is called the authentication server. The switch, which does in some way translate between message formats for this process, plays the role that 802.1x defines as authenticator. |
27.
Which of the following answers is true of TACACS+ but not true of RADIUS?
- A.The protocol encrypts the password for transmission.
- B.Uses UDP as the transport protocol.
- C.Supports ability to authorize different users to use different subsets of CLI commands.
- D.Defined by an RFC
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| TACACS+, defined by Cisco, uses TCP as its transport protocol. Cisco defines TACACS+ with an ability to authorize users for different subsets of CLI commands, whereas RADIUS does not. Both RADIUS and TACACS+ encrypt the passwords before transmitting them. |
28.
An engineer hears about DHCP snooping and decides to implement it. The network
includes devices that act primarily as Layer 2 switches, multilayer switches (that is,
they perform both Layer 2 and Layer 3 switching), and Routers. Which of the following are the devices on which DHCP snooping could be implemented? (Choose two
answers.)
- A.Layer 2 switches
- B.Routers
- C.Multilayer switches
- D.A LAN hub
- Answer & Explanation
- Report
Answer : [A and C]
Explanation :
Explanation :
| DHCP snooping must be implemented on a device that does Layer 2 switching. The DHCP snooping function needs to examine DHCP messages that flow between devices within the same broadcast domain (VLAN). Layer 2 switches perform that function, as well as multilayer switches. Because a Router performs only Layer 3 forwarding (that is, routing), and does not forward messages between devices in the same VLAN, a Router does not provide a good platform to implement DHCP snooping (and is not even a feature of Cisco IOS on Routers). |
29.
Layer 2 switch SW2 connects to several devices: a Layer 2 switch (SW1), a Router, a
DHCP server, and three PCs (PC1, PC2, and PC3). All PCs are expected to use DHCP
to lease their IP addresses. A network engineer implements DHCP snooping on switch
SW2. Unknown to the engineer, a malicious attacker is using PC3. Which of the following is the most likely DHCP snooping trust state configuration on SW2 for the
ports connected to the listed devices? (Choose two answers.)
- A.The port connected to the Router is untrusted.
- B.The port connected to switch SW1 is trusted.
- C.The port connected to PC1 is untrusted.
- D.The port connected to PC3 is trusted.
- Answer & Explanation
- Report
Answer : [B and C]
Explanation :
Explanation :
| Switch ports connected to IT-controlled devices from which DHCP messages may be received should be trusted by the DHCP snooping function. Those devices include IT-controlled DHCP servers and IT-controlled Routers and switches. All devices that are expected to be DHCP client devices (like PCs) are then treated as untrusted, because DHCP snooping cannot know beforehand from which ports a DHCP-based attack will be launched. In this case, the ports connected to all three PCs will be treated as untrusted by DHCP snooping. |
30.
A network engineer takes four 2960-X switches and creates a switch stack using
either FlexStack or FlexStack-Plus stacking from Cisco. Now consider data plane
functions, such as frame forwarding; control plane functions, such as STP and VTP;
and management plane functions, such as Telnet and SSH support. Once the stack
is cabled and working, which of the following is true about how the stack of four
switches works?
- A.The stack acts as one switch for data plane functions, and separate switches for control and management plane functions.
- B.The stack acts as one switch for data plane and control plane functions, and separate switches for management plane functions.
- C.The stack acts as one switch for data plane, control plane, and management plane functions.
- D.The stack does not act as one switch for data, control, or management plane functions, instead providing backup uplinks if all of one switch's uplinks fail.
- Answer & Explanation
- Report
Answer : [C]
Explanation :
Explanation :
| A switch stack connects the switches with stacking modules and stacking cables so that they can communicate directly. Functionally, the switches in the stack act as a single logical switch. For instance, to manage the switches in the stack, an engineer would log in to one switch, with one IP address, and see one configuration file for the whole switch stack; STP and VTP would run for the logical switch as a whole; and frame forwarding would occur on one switch, forwarding on all ports in the stack. |
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