Which does DHCP option 66 provide?

Which does DHCP option 66 provide?

• PXE bootfile name
• DHCP user class
• The IP address or the hostname of a single TFTP server
• A list of TFTP servers 

EXPLANATION

DHCP option 66 gives the IP address or the hostname of a single TFTP server.

 

TFTP server name

   This option is used to identify a TFTP server when the 'sname' field
   in the DHCP header has been used for DHCP options.



   The code for this option is 66, and its minimum length is 1.

       Code  Len   TFTP server
      +-----+-----+-----+-----+-----+---
      | 66  |  n  |  c1 |  c2 |  c3 | ...
      +-----+-----+-----+-----+-----+---

 

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Which switch would STP choose to become the root bridge in the selection process?

Which switch would STP choose to become the root bridge in the selection process?

• 32768: 22-33-44-55-66-77
• 32769: 11-22-33-44-55-65
• 32768: 11-22-33-44-55-66
• 32769: 22-33-44-55-66-78 

EXPLANATION

Since the BID starts with the Bridge Priority field, essentially, the switch with the lowest Bridge Priority field becomes the Root Bridge. If there is a tie between two switches having the same priority value, then the switch with the lowest MAC address becomes the Root Bridge.

 

One of the most confusing things to understand when learning about the switched part of network is the Spanning Tree Protocol (STP – 802.1D) and how it works to allow traffic to be efficiently forwarded through the switched network. This article will take a look at the STP path selection process, how a root switch is elected, how root and designated ports are assigned, and how each switch port is determined to be a root or a designated port as well as which ports will be forwarding or blocking.

STP Root Bridge / Root Switch Selection

The first question to really ask is: What is a root bridge? On an STP network, the root bridge (also known as a root switch)
is intended to be the top of the forwarding pyramid, the forwarding decisions for the rest of the switched network depend on the location of the root bridge. The selection of the root bridge is determined by the bridge configured priority; by default this would be the switch with the lowest MAC address. It is important for anyone building a network using STP to ensure that the location of the root bridge is relatively central to the switched network so that forwarding decisions are made as efficiently as possible. This is possible because each switch can be configured with a lower bridge priority, which ensures it becomes the root switch.

Path Selection

Once the root bridge has been selected (or elected), the formation of the forwarding tables can begin. One concept that must first be reviewed, however, is the idea of STP interface costs. Depending on the speed of the connected interfaces on the switches, they will be assigned a specific STP cost, these costs are then used to determine the total cost from the current switch to the root switch. Each of the switches throughout the network will send STP traffic between each other to determine this total path cost.

SOURCE

https://www.petri.com/stp-spanning-tree-protocol-path-selection

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When it comes to hardware, what does NIC stand for?

When it comes to hardware, what does NIC stand for?

• Network Internal Connection
• Network Interface Card
• Network Interface Connection
• Network Interconnect Card

EXPLANATION

NIC is short for network interface card.It's network adapter hardware in the form of an add-in card that fits in an expansion slot on a computer's motherboard.
Most computers have them built-in — in which case they're just a part of the circuit board — but you can also add your own NIC to expand the functionality of the system.

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You've been asked to move from IPv4 to IPv6. What is a valid reason for adopting IPv6 over IPv4?

You've been asked to move from IPv4 to IPv6. What is a valid reason for adopting IPv6 over IPv4?

• Telnet access does not require a password
• Change of destination address in the IPv6 header
• No broadcast
• Change of source address in the IPv6 header 

EXPLANATION

IPv6 does not implement traditional IP broadcast, and therefore does not define broadcast addresses. In IPv6, the same result can be achieved by sending a packet to the link-local all nodes multicast group which is analogous to IPv4 broadcast.

An IP address serves the purpose of identifying an individual network interface of a host, locating it on the network, and thus permitting the routing of IP packets between hosts. ... In contrast to IPv4, which defined an IP address as a 32-bit value, IPv6 addresses have a size of 128 bits.

 

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In SQL, what does the MULTI_USER option do?

In SQL, what does the MULTI_USER option do?

• Allows one user at a time to connect to the DB
• Allows some members to access the DB
• Allows users with correct permissions to connect
• Allows only the system admins to connect 

EXPLANATION

 A multiuser environment is one in which other users can connect and make changes to the same database that you are working with. As a result, several users might be working with the same database objects at the same time. ... A key issue when working with databases in a multiuser environment is access permissions.

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In SQL Server, A database is in single-user mode and ready to be repaired or restored when it is in which of the following states?

In SQL Server, A database is in single-user mode and ready to be repaired or restored when it is in which of the following states?

• EMERGENCY
• OFFLINE
• RECOVERY PENDING
• SUSPECT

EXPLANATION

Database State Definitions

The following table defines the database states.

State	Definition
ONLINE	Database is available for access. The primary filegroup is online, although the undo phase of recovery may not have been completed.
OFFLINE	Database is unavailable. A database becomes offline by explicit user action and remains offline until additional user action is taken. For example, the database may be taken offline in order to move a file to a new disk. The database is then brought back online after the move has been completed.
RESTORING	One or more files of the primary filegroup are being restored, or one or more secondary files are being restored offline. The database is unavailable.
RECOVERING	Database is being recovered. The recovering process is a transient state; the database will automatically become online if the recovery succeeds. If the recovery fails, the database will become suspect. The database is unavailable.
RECOVERY PENDING	SQL Server has encountered a resource-related error during recovery. The database is not damaged, but files may be missing or system resource limitations may be preventing it from starting. The database is unavailable. Additional action by the user is required to resolve the error and let the recovery process be completed.
SUSPECT	At least the primary filegroup is suspect and may be damaged. The database cannot be recovered during startup of SQL Server. The database is unavailable. Additional action by the user is required to resolve the problem.
EMERGENCY	User has changed the database and set the status to EMERGENCY. The database is in single-user mode and may be repaired or restored. The database is marked READ_ONLY, logging is disabled, and access is limited to members of the sysadmin fixed server role. EMERGENCY is primarily used for troubleshooting purposes. For example, a database marked as suspect can be set to the EMERGENCY state. This could permit the system administrator read-only access to the database. Only members of the sysadmin fixed server role can set a database to the EMERGENCY state.

Database State Definitions

The following table defines the database states.

State	Definition
ONLINE	Database is available for access. The primary filegroup is online, although the undo phase of recovery may not have been completed.
OFFLINE	Database is unavailable. A database becomes offline by explicit user action and remains offline until additional user action is taken. For example, the database may be taken offline in order to move a file to a new disk. The database is then brought back online after the move has been completed.
RESTORING	One or more files of the primary filegroup are being restored, or one or more secondary files are being restored offline. The database is unavailable.
RECOVERING	Database is being recovered. The recovering process is a transient state; the database will automatically become online if the recovery succeeds. If the recovery fails, the database will become suspect. The database is unavailable.
RECOVERY PENDING	SQL Server has encountered a resource-related error during recovery. The database is not damaged, but files may be missing or system resource limitations may be preventing it from starting. The database is unavailable. Additional action by the user is required to resolve the error and let the recovery process be completed.
SUSPECT	At least the primary filegroup is suspect and may be damaged. The database cannot be recovered during startup of SQL Server. The database is unavailable. Additional action by the user is required to resolve the problem.
EMERGENCY	User has changed the database and set the status to EMERGENCY. The database is in single-user mode and may be repaired or restored. The database is marked READ_ONLY, logging is disabled, and access is limited to members of the sysadmin fixed server role. EMERGENCY is primarily used for troubleshooting purposes. For example, a database marked as suspect can be set to the EMERGENCY state. This could permit the system administrator read-only access to the database. Only members of the sysadmin fixed server role can set a database to the EMERGENCY state.

  The database can be changed to the EMERGENCY state by a sysadmin user action, in order to safely perform database maintenance or for troubleshooting purposes. In this state, the database will be in single-user mode to be repaired or restored, marked as READ_ONLY where you can export the data out of the database, logging is disabled and the access is restricted only to the sysadmin role members.
Let us get back again to the previous SuspectDBDemo corrupted database that is marked as SUSPECT. In order to troubleshoot its problem and resolve it, we will change the database state to EMERGENCY, permitting the sysadmin users read-only access to that database. The below ALTER DATABASE statement is used to set the database state to EMERGENCY:

ALTER DATABASE SuspectDBDemo SET EMERGENCY

GO

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In networking, what does the acronym STP refer to?

In networking, what does the acronym STP refer to?

• Secure Telephony Procedure
• Stacked Terminal Policy
• Standard Topology Practice
• Spanning Tree Protocol 

EXPLANATION

The Spanning Tree Protocol (STP) is a network protocol that builds a loop-free logical topology for Ethernet networks. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them.
Spanning-Tree Protocol (STP) is a link management protocol that provides path redundancy while preventing undesirable loops in the network. ... In a STP environment, the switches exchange information amongst themselves using bridge protocol data units (BPDU) and will then listen in on all ports for this BPDU message. 

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