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In a multi-vendors switch implementation, a network engineer notices that directly connected devices that use CDP are not visible. Which standard protocol could be used to resolve this issue?
A. Local Area Mobility
B. Link Layer Discovery Protocol
C. NetFlow
D. Logical Link Discovery Protocol
Answer: B.
The Link Layer Discovery Protocol (LLDP) is defined in the IEEE 802.1AB standard for link layer protocol in the Internet Protocol Suite used by network devices for advertising their identity, capabilities and neighbors on an IEEE 802 local area network, principally wired Ethernet. LLDP functions in a similar way as several proprietary protocols, such as the Cisco Discovery Protocol (CDP).
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TSHOOT – Troubleshooting and Maintaining Cisco IP Networks v2.0
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Smith is an IT security consultant who has been hired on by an ISP that has recently been plagued by numerous DoS attacks. The ISP did not have the internal resources to prevent future attacks, so they hired Smith for his expertise. Smith looks through the company’s firewall logs and can see from the patterns that the attackers were using reflected DoS attacks. What measures can Smith take to help prevent future reflective DoS attacks against the ISP’s network?
A. Smith needs to tell the ISP to block all UDP traffic coming in on port 1001 to prevent future reflective DoS attacks against their network.
B. Smith should configure the ISP’s firewall so that it blocks FIN packets that are sent to the broadcast address of the company’s internal IP range.
C. Smith should have them configure their network equipment to recognize SYN source IP addresses that never complete their connections.
D. Smith should have the ISP block port 443 on their firewall to stop these DoS attacks.
The correct answer is C.
Attackers send packets to the reflector servers with a source IP address set to their victim’s IP therefore indirectly overwhelming the victim with the response packets. As victim is not expecting these response packets, it will drop the packets thus terminating the connections.
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Which two Cisco Nexus switches are capable of Layer 3 switching? (Choose two.)
A. Cisco Nexus 7010
B. Cisco Nexus 5020
C. Cisco Nexus 5548
D. Cisco Nexus 2248
E. Cisco Nexus 2232
Answer: A and C.
The Nexus 2200 series are extenders and not switches. They attach to a switch, but have no local switching capability. The first generation 5000 series (5010 and 5020) were layer 2 only. So from the list, only the 7010 and the 5548 are capable of layer 3 forwarding. That is assuming that the 5548 has the layer 3 daughter board installed.
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Interface FastEthernet0/1 is configured as a trunk that permits all VLANs. The following command is configured: monitor session 2 filter vlan 1 – 8, 39, 52
What is the result of the implemented command?
A. All VLAN traffic is sent to the SPAN destination interface.
B. Traffic from all VLANs, except 1 to 8, 39 and 52 are sent to the SPAN destination interface.
C. Filtering a trunked SPAN port is not supported.
D. The trunk’s native VLAN must be changed from its default VLAN 1.
E. Traffic from VLANs 1 to 8, 39, and 52 are sent to the SPAN destination port.
Answer: E.
The “monitor session filter” command is used to specify which VLANS are to be port mirrored using SPAN feature.
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Which of the following encryptions are not based on a block cipher?
A. AES (Rijndael)
B. DES
C. Blowfish
D. RC4
The correct answer is D.
RC4 (Rivest Cipher 4) is a stream cipher. In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks, with an unvarying transformation that is specified by a symmetric key. Block ciphers are important elementary components in the design of many cryptographic protocols, and are widely used to implement encryption of bulk data.
Notable block ciphers:
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Which three are features of Cisco OTV? (Choose three.)
A. Control plane-based MAC learning
B. Dynamic encapsulation
C. MAC address learning based on flooding
D. Pseudo wires and tunnels
E. Complex dual-homing
F. Native automated multihoming
Answer: A, B and F.
Per Cisco: OTV introduces the concept of “MAC routing,” which means a control plane protocol is used to exchange MAC reachability information between network devices providing LAN extension functionality. This is a significant shift from Layer 2 switching that traditionally leverages data plane learning, and it is justified by the need to limit flooding of Layer 2 traffic across the transport infrastructure. As emphasized throughout this document, Layer 2 communications between sites resembles routing more than switching. If the destination MAC address information is unknown, then traffic is dropped (not flooded), preventing waste of precious bandwidth across the WAN.
OTV also introduces the concept of dynamic encapsulation for Layer 2 flows that need to be sent to remote locations. Each Ethernet frame is individually encapsulated into an IP packet and delivered across the transport network. This eliminates the need to establish virtual circuits, called Pseudowires, between the data center locations. Immediate advantages include improved flexibility when adding or removing sites to the overlay, more optimal bandwidth utilization across the WAN (specifically when the transport infrastructure is multicast enabled), and independence from the transport characteristics (Layer 1, Layer 2 or Layer 3).
Finally, OTV provides a native built-in multi-homing capability with automatic detection, critical to increasing high availability of the overall solution. Two or more devices can be leveraged in each data center to provide LAN extension functionality without running the risk of creating an end-to-end loop that would jeopardize the overall stability of the design. This is achieved by leveraging the same control plane protocol used for the exchange of MAC address information, without the need of extending the Spanning-Tree Protocol (STP) across the overlay.
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Which set of configurations will result in the member ports on switch 1 and 2 to bundling into an EtherChannel?
A. Switch1(inf-range)# channel-group 1 mode active
Switch2(inf-range)# channel-group 1 mode auto
B. Switch1(inf-range)# channel-group 1 mode desirable
Switch2(inf-range)# channel-group 1 mode passive
C. Switch1(inf-range)# channel-group 1 mode on
Switch2(inf-range)# channel-group 1 mode auto
D. Switch1(inf-range)# channel-group 1 mode desirable
Switch2(inf-range)# channel-group 1 mode auto
Answer: D.
With Etherchannel negotiations, the protocol configuration fallowing to try to bring up a channel:
PaGP: Auto to Auto – no channel
Auto to Desirable – channel
Desirable to Desirable – channel
LACP: Passive to Passive – no channel
Passive to Active – channel
Active to Active – channel
No protocol (ON):
On to On is the only valid combination, anything else will cause the member links to fail.
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NetBIOS over TCP/IP allows files and/or printers to be shared over the network. You are trying to intercept the traffic from a victim machine to a corporate network printer. You are attempting to hijack the printer network connection from your laptop by sniffing the wire.
Which port does SMB over TCP/IP use?
A. 443
B. 179
C. 445
D. 139
The correct answer is C.
Port 445 – Microsoft-DS SMB file sharing
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It seems that even with all the examples of breaches and compromises caused by the lack of company security across the last two decades, organizations continue to move forward with a “same as it ever was” mentality. Organizations aren’t learning from others’ mistakes.
I predict that in 2016, hackers will continue to compromise organizations’ systems in ways that could have been prevented with common sense security solutions or by stress-testing their own implementations.
Here are seven obvious, but often forgotten, security measures you should have in place:
Testing should always be performed to ensure productivity and functionality, but staying on older versions is usually less secure.
For example, a customer’s billing data should be separate from their login credentials, which should also be separate from their profile settings, preferences and activity history.
To do this, filter input against length requirements while pattern matching against a known list of malicious signatures, and escaping metacharacters. Metacharacters are characters assigned a special meaning by a programming language or execution environment.
These and other standard security concepts are well established, but not as widely adopted as they should be. As new organizations come online, expand their Internet presence, or roll out new products, they often make the same security mistakes as many others did before them.
As consumers, we’ve become created a lax security culture. We have established the trend that we will purchase new products in spite of flaws and failures. Often the early adopters of a new product are more like beta testers than typical consumers, willing to live with and work around problems just for the sake of getting the new thing in their hands. But that doesn’t mean we have to continue to be willing beta testers.
We should only purchase products and use services that have a strong proven track record when it comes to security. One way encourage better products on the market, and deter hackers, is to push for more transparency. Organizations should publish their security standards, thus allowing us to review their practices and make informed decisions about who is doing the better job at protecting our information. This idea is already established in the digital certificate marketplace through a certificate authority’s publication of its certificate practices statements (CPS). A similar strategy or publishing security practices should be applied across most or all of IT-related industries. Perhaps if we, as consumers, demand transparency and stronger security features from our vendors and suppliers, maybe 2016 will be the year that cybersecurity takes a huge leap forward.
Read more cybersecurity tips and precautions in the white paper Cybersecurity Predictions for 2016.
Which two Cisco data center devices can support FabricPath? (Choose two.)
A. Cisco Nexus 5500 Series Switches
B. Cisco Nexus 1000V
C. Cisco Nexus 7000 Series Switches
D. Cisco Nexus 4900 Series Switches
E. Cisco MDS 9500 Series directors
Answer: A and C.
From the list of devices, only the 5500 and 7000 series support FabricPath, though now the 6000 series do as well.
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