Cisco 351-001 Online Practice Questions and Exam Preparation

Cisco 351-001 Online Questions & Answers

• Question 871:

  Which two statements about native VLANs are true? (Choose two) A. They are configured under the trunk interface.

  B. They are configured in VLAN database mode.
  C. They are used to forward untagged traffic only.
  D. They are used to forward tagged traffic only.
  E. They require VTPv3.
  F. They are used to forward both tagged and untagged traffic.
  B. They are configured in VLAN database mode.
  F. They are used to forward both tagged and untagged traffic.

• Question 872:

  Which two functions are performed by the DR in OSPF? (Choose two.)

  A. The DR originates the network LSA on behalf of the network.
  B. The DR is responsible for the flooding throughout one OSPF area.
  C. The DR forms adjacencies with all other OSPF routers on the network, in order to synchronize the LSDB across the adjacencies.
  D. The DR is responsible for originating the type 4 LSAs into one area.
  A. The DR originates the network LSA on behalf of the network.
  C. The DR forms adjacencies with all other OSPF routers on the network, in order to synchronize the LSDB across the adjacencies.

  ---

  The DR originates the network LSA (LSA Type 2) which lists all the routers on the segment it is adjacent to -> A is correct. Types 2 are ooded within its area only; does not cross ABR -> B is incorrect. The broadcast and non-broadcast network types elect a DR/BDR. They form adjacencies to all other OSPF routers on the network and help synchronize the Link State Database (LSDB) across the adjacencies -> C is correct. LSAs Type 4 are originated by the ABR to describe an ASBR to routers in other areas so that routers in other areas know how to get to external routes through that ASBR -> D is incorrect.

• Question 873:

  Which two statements about redistribution are true? (Choose two.)

  A. EIGRP requires the route to have a default metric defined.
  B. EIGRP and OSPF use their router IDs to prevent loops.
  C. When OSPF is redistributed into IS-IS, the default metric must be configured under the IS-IS process.
  D. When traffic is redistributed into OSPF, the subnets command is needed to redistribute classful subnets.
  E. The default seed metric for OSPF redistributed routes is 30.
  A. EIGRP requires the route to have a default metric defined.
  B. EIGRP and OSPF use their router IDs to prevent loops.

• Question 874:

  Refer to the exhibit.

  

  Which statement about this GET VPN configuration is true?

  A. Router 1 acts as the primary key server because it has a higher priority.
  B. An RSA key has been imported into the configuration.
  C. The GDOI group configuration generated a key.
  D. DPD is disabled.
  A. Router 1 acts as the primary key server because it has a higher priority.

• Question 875:

  What is a disadvantage of using aggressive mode instead of main mode for ISAKMP/IPsec establishment?

  A. It does not use Diffie-Hellman for secret exchange.
  B. It does not support dead peer detection.
  C. It does not support NAT traversal.
  D. It does not hide the identity of the peer.
  D. It does not hide the identity of the peer.

  ---

  IKE phase 1's purpose is to establish a secure authenticated communication channel by using the Diffieellman key exchange algorithm to generate a shared secret key to encrypt further IKE communications. This negotiation results in one single bi-directional ISAKMP Security Association (SA). The authentication can be performed using either pre- shared key (shared secret), signatures, or public key encryption.Phase 1 operates in either Main Mode or Aggressive Mode. Main Mode protects the identity of the peers; Aggressive Mode does not.

  Reference: http://en.wikipedia.org/wiki/Internet_Key_Exchange

• Question 876:

  According to RFC 4577, OSPF for BGP/MPLS IP VPNs, when must the down bit be set?

  A. when an OSPF route is distributed from the PE to the CE, for Type 3 LSAs
  B. when an OSPF route is distributed from the PE to the CE, for Type 5 LSAs
  C. when an OSPF route is distributed from the PE to the CE, for Type 3 and Type 5 LSAs
  D. when an OSPF route is distributed from the PE to the CE, for all types of LSAs
  C. when an OSPF route is distributed from the PE to the CE, for Type 3 and Type 5 LSAs

  ---

  If an OSPF route is advertised from a PE router into an OSPF area, the Down bit (DN) is set. Another PE router in the same area does not redistribute this route into iBGP of the MPLS VPN network if down is set.

  RFC 4577 says:

  "When a type 3 LSA is sent from a PE router to a CE router, the DN bit in the LSA Options field MUST be set. This is used to ensure that if any CE router sends this type 3 LSA to a PE router, the PE router will not redistribute it further. When

  a PE router needs to distribute to a CE router a route that comes from a site outside the latter's OSPF domain, the PE router presents itself as an ASBR (Autonomous System Border Router), and distributes the route in a type 5 LSA. The DN

  bit [OSPF-DN] MUST be set in these LSAs to ensure that they will be ignored by any other PE routers that receive them."

  For more information about Down bit according to RFC 4577 please read more herE. http://tools.ietf.org/html/rfc4577#section-4.2.5.1.

• Question 877:

  Refer to the exhibit.

  

  R1 is configured as shown. R1 is able to establish a neighbor adjacency only with R2. Which addition must you make to the R1 configuration to allow it to establish an adjacency with R3?

  A. interface gigabitethernet 0/1 ip address 10.1.0.1 255.255.255.0 ip ospf network point-to-point
  B. interface gigabitethernet 0/1 ip address 10.1.0.1 255.255.255.0 ip ospf 1 area 0
  C. router ospf 1 network 10.1.0.0 0.0.0.255 area 1
  D. router ospf 1 area 0 stub
  C. router ospf 1 network 10.1.0.0 0.0.0.255 area 1

  ---

  To enable interfaces and networks with OSPF, the networks need to be specified in the network statement. In the configuration shown, only 10.0.0.0/24 has been enabled, we are missing the network connecting to R3 (10.1.0.0/24).

• Question 878:

  Which technology can be used to secure the core of an STP domain?

  A. UplinkFast
  B. BPDU guard
  C. BPDU filter
  D. root guard
  D. root guard

  ---

  Since STP does not implement any authentication or encryption to protect the exchange of BPDUs, it is vulnerable to unauthorized participation and attacks. Cisco IOS offers the STP Root Guard feature to enforce the placement of the root

  bridge and secure the core of the STP domain. STP root guard forces a port to become a designated port so that no switch on the other end of the link can become a root switch. If a port configured for root guard receives a superior BPDU,

  the port it is received on is blocked. In this way, STP root guard blocks other devices from trying to become the root bridge. STP root guard should be enabled on all ports that will never connect to a root bridge, for example, all end user ports.

  This ensures that a root bridge will never be negotiated on those ports.

  Reference:

  http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Security/Baseline_Security/secur ebasebook/sec_chap7.html

• Question 879:

  Refer to the exhibit.

  

  You are configuring the S1 switch for the switchport connecting to the client computer. Which option describes the effect of the command mls qos map cos-dscp 0 8 16 24 32 40 46 56?

  A. Voice traffic is excluded from the default priority queue.
  B. Voice packets are given a class selector of 5.
  C. Video conferencing is marked CS3.
  D. Voice packets are processed in the priority queue.
  A. Voice traffic is excluded from the default priority queue.

  ---

  The default CoS to DSCP mappings are shown below:

  Default CoS-to-DSCP Map

  CoS Value DSCP Value In our example, we see that COS 6 is mapped to DSCP, not the default of DSCP 48 as shown above. DSCP 46 is Expedited Forwarding (EF), which is typically used for voice traffic, and this value has not been included in this class map.

• Question 880:

  Which two statements about NPTv6 are true? (Choose two.)

  A. The translation is invisible to applications that hard code IP information within the application logic.
  B. It is a one-way stateful translation for the IPv6 address.
  C. Translation is 1:1 at the network layer.
  D. It is a two-way stateless translation for the network prefix.
  C. Translation is 1:1 at the network layer.
  D. It is a two-way stateless translation for the network prefix.

  ---

  This document describes a stateless, transport-agnostic IPv6-to-IPv6 Network Prefix Translation (NPTv6) function that provides the address-independence benefit associated with IPv4-to-IPv4 NAT (NAPT44) and provides a 1:1 relationship between addresses in the "inside" and "outside" prefixes, preserving end-to-end reachability at the network layer NPTv6 Translation is stateless, so a "reset" or brief outage of an NPTv6 Translator does not break connections that traverse the translation function, and if multiple NPTv6 Translators exist between the same two networks, the load can shift or be dynamically load shared among them. NPTv6 is defined to include a two-way, checksum-neutral, algorithmic translation function, and nothing else.

  Reference: https://tools.ietf.org/html/rfc6296