Which WMI class can you use to determine a system's last bootup time?

Which WMI class can you use to determine a system's last bootup time?

• Win32_OperatingSystem
• Win32_BootEvent
• Win32_ComputerSystem
• Win32_BIOS             

EXPLANATION

Win32_OperatingSystem includes a property called LastBootUpTime, which is the time when the system last booted up.
Win32_ComputerSystem and Win32_BIOS do not have any properties that can be used for this.
Win32_BootEvent does not exist.

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Which encoding would allow you to transmit binary data over an ASCII-only communications channel?

Which encoding would allow you to transmit binary data over an ASCII-only communications channel?

• Unicode
• bytecode
• Base64
• ISO-8851-1 

 

EXPLANATION

Base64 is a format that encodes arbitrary binary data into ASCII characters (letters, digits and limited punctuation).  These characters then can be decoded back into binary at the other end.
  This allows transmitting binary data over channels that normally only allow ASCII (such as email or display terminals).  Base64 takes up 1/3 more space than the equivalent binary format.

SOURCE

https://en.wikipedia.org/wiki/Base64

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In SCCM, which of the following can build and capture and subsequently deploy an OS image from a set of operating system installation files, install additional applications during the build-phase and capture and restore user state information?

In SCCM, which of the following can build and capture and subsequently deploy an OS image from a set of operating system installation files, install additional applications during the build-phase and capture and restore user state information?

• Task Sequence
• Task Scheduler
• Task Manager
• Tasklist 

 

EXPLANATION

System Center Configuration Manager uses task sequences to automatically install an operating system image on a destination computer. You create a task sequence that references a boot image used to start the destination computer, the operating system image that you want to install on the destination computer, and any other additional content, such as other applications or software updates, that

SOURCE

https://technet.microsoft.com/en-us/library/bb693631.aspx

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In order to SEND email reliably, a mailserver MUST meet the following DNS requirement:

In order to SEND email reliably, a mailserver MUST meet the following DNS requirement:

• SPF and DKIM records
• A valid MX record
• A PTR record which matches the email domain
• A valid PTR record 

 

EXPLANATION

A sending mailserver shall have a valid PTR (reverse DNS lookup) record for its public IP address. That is, the PTR record must return the same IP address if submitted to a DNS lookup. If this is not the case, the recipient is likely to reject the mail as possible spam. (If IPv6 is used this also applies here, a point often overlooked)

MX records determine which computers accept inbound mail for

SOURCE

https://www.studiocoast.com.au/knowledgebase/194/email/support.aspx

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In IT, the term kilobyte (KB) is traditionally used to connote which of the following?

In IT, the term kilobyte (KB) is traditionally used to connote which of the following?

• 10000 bytes
• 1024 bytes
• 512 bytes
• 2048 bytes 

 

EXPLANATION

Because computers are binary (base 2) instead of decimal (base 10), 1KB would be 2 to the 10th bytes, or 1024.

In fact, the definition of KB (kilobytes) was changed in 1998 to match up with SI units, the current term for 1024 bytes is Kibibyte (https://en.wikipedia.org/wiki/Kibibyte). That said, most IT pros still prefer the traditional definition of KB as 1024 bytes, since it's the most common way to refer to computing capacity.

For further information about these terms, see http://www.iec.ch/si/binary.htm andhttp://physics.nist.gov/cuu/Units/binary.html

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What logic construct most efficiently allows you to execute one of a number of code blocks based on the value of a single variable?

What logic construct most efficiently allows you to execute one of a number of code blocks based on the value of a single variable?

• while
• if
• switch
• for 

EXPLANATION

You can supply a variable to a "switch" statement, and provide a code block for each possible value.
Example using PowerShell:

switch ($var) {
    1 { <# Executes if $var = 1 #> }
    2 { <# Executes if $var = 2 #> }
    3 { <# Executes if $var = 3 #> }
    4 { <# Executes if $var = 4 #> }
    default { <# Executes if $var doesn't match any other case #> }
}

A single "switch" can take the place of a chain of "if/elseif/else".
"for" and "while" are both loops.

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What can be used to protect you from receiving email messages with a forged sender address?

What can be used to protect you from receiving email messages with a forged sender address?

• SPF
• Secure SMTP
• Digital ID
• IMAP 

 

EXPLANATION

Sender Policy Framework (SPF) is a simple email-validation system designed to detect email spoofing by providing a mechanism to allow receiving mail exchangers to check that incoming mail from a domain comes from a host authorized by that domain's administrators.[1] The list of authorized sending hosts for a domain is published in the Domain Name System (DNS) records for that domain in the form of a specially formatted TXT record. Email spam and phishing often use forged "from" addresses, so publishing and checking SPF records can be considered anti-spam techniques.
IETF publication RFC 7208 dated April 2014 defines Sender Policy Framework as "proposed standard".

SOURCE

https://en.wikipedia.org/wiki/Sender_Policy_Framework

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