You are the network administrator for your company and have configured Cisco Discovery Protocol (CDP) in your network. You recently noticed that when devices send large numbers of CDP neighbor announcements, some devices are crashing. You decide to disable CDP on the router. Which command should you use to achieve the objective?
A. no cdp run
B. set cdp disable
C. no cdp enable
D. no cdp advertise-v2
Correct Answer: A
You should use the no cdp run command to disable CDP on the router. Due to a known vulnerability regarding the handling of CDP by Cisco routers and switches when devices send large numbers of CDP neighbor announcements, some devices can crash or cause abnormal system behavior. To overcome this problem, you can disable CDP for the entire router by using the no cdp run command. You cannot use the set cdp disable command to disable CDP on the router. This command disables CDP on an entire Catalyst switch. You cannot use the no cdp enable command to disable CDP on the router. This command disables CDP on a specific interface. You cannot use the no cdp advertise-v2 command to disable CDP on the router. This command disables CDPv2 advertisements.
LAN Switching Fundamentals
Configure and verify Layer 2 protocols
Cisco > Support > Using Cisco Discovery Protocol
Cisco > Support > Technology Support > Network Management > Cisco’s Response to the CDP Issue > Document ID: 13621
Which is NOT a valid range for private IP addresses?
A. 10.0.0.0 – 10.255.255.255
B. 172.16.0.0 – 172.31.255.255
C. 192.168.0.0 – 192.168.255.255
Correct Answer: D
The range 188.8.131.52 – 184.108.40.206 is a valid public IP address range, not a private IP address range.
The Internet Assigned Numbers Authority (IANA) has reserved the following three ranges for private Internet use:
10.0.0.0 – 10.255.255.255 (10.0.0.0/8)
172.16.0.0 – 172.31.255.255 (172.16.0.0/12)
192.168.0.0 – 192.168.255.255 (192.168.0.0/16)
The Internet Assigned Numbers Authority (IANA) manages and distributes global public IP addresses. IANA also performs DNS root zone management. IANA operates with the help of International Engineering Task Force (IETF) and RFC Editor to manage IP address allocation and DNS root zone management. There are Regional Internet Registries (RIRs) through which IANA allocates local registrations of IP addresses to different regions of the world. Each RIR handles a specific region of the world.
Describe the need for private IPv4 addressing
Which of the following protocols allow
Correct Answer: AC
Both Per VLAN Spanning Tree Plus (PVST+) and Per VLAN Rapid Spanning Tree (PVRST) protocols allow for a spanning tree instance for each VLAN, allowing for the location optimization of the root bridge for each VLAN. These are Cisco proprietary enhancements to the 802.1d and 802.1w standards, respectively.
Rapid Spanning Tree Protocol (RSTP) is another name for the 802.1w standard. It supports only one instance of spanning tree.
Spanning Tree Protocol (STP) is another name for the 802.1d standard. It supports only one instance of spanning tree.
LAN Switching Fundamentals
Configure, verify, and troubleshoot STP protocols
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