IT Questions and Answers :)

Friday, June 21, 2019

A DNS SPF record is for:

A DNS SPF record is for:

  • Identifying mail server IP address(es) authorized to send on a domains behalf
  • Resolving an ip address from a fully qualified host name
  • Resolving the address of a mail server responsible for accepting mail messages on behalf of a domain
  • Resolving an alias name to a host 

A DNS SPF record is for:

EXPLANATION

A Sender Policy Framework (SPF) record is a type of Domain Name Service (DNS) TXT record that identifies which mail servers are permitted to send email on behalf of your domain. The purpose of an SPF record is to detect and prevent spammers from sending messages with forged From addresses on your domain.  

An SPF record is a Sender Policy Framework record. It's used to indicate to mail exchanges which hosts are authorized to send mail for a domain. It's defined in RFC 4408, and clarified by RFC 7208. SPF record format. SPF records are typically defined using the TXT record type.

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What was "SystemPro"

What was "SystemPro"

  • The working title for AMD
  • The "first" real PC based Server.
  • The first chip from Intel
  • The first user group for system administrators 
What was "SystemPro"

EXPLANATION

Compaq SystemPro

The SystemPro from Compaq, released in November 1989, was arguably the first true PC based server. It supported Intel's 486 chip, a 32-bit bus, RAID disk and dual-processor support well before its main rivals. 



Innovative features

The SystemPro, along with the simultaneously released Compaq Deskpro 486, was one of the first two commercially available computer systems containing the new EISA bus. The SystemPro was also one of the first PC-style systems specifically designed as a network server, and as such was built from the ground up to take full advantage of the EISA bus. It included such features as multiprocessing (the original systems were asymmetric-only), hardware RAID, and bus-mastering network cards. All models of SystemPro used a full-height tower configuration, with eight internal hard drive bays

 

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In .NET, which of the following is NOT a value type?

In .NET, which of the following is NOT a value type?

  • double
  • char
  • int
  • string

In .NET, which of the following is NOT a value type?

EXPLANATION

Main features of value types

A variable of a value type contains a value of the type. For example, a variable of the int type might contain the value 42. This differs from a variable of a reference type, which contains a reference to an instance of the type, also known as an object.
When you assign a new value to a variable of a value type, that value is copied. When you assign a new value to a variable of a reference type, the reference is copied, not the object itself.

Source

https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/value-types

 

 
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In which version of Windows Server was Microsoft IPAM first released?

In which version of Windows Server was Microsoft IPAM first released?

  • Windows Server 2012
  • Windows Server 2008
  • Windows Server 2012 R2
  • Windows Server 2003 
In which version of Windows Server was Microsoft IPAM first released?

EXPLANATION

 IPAM or IP Address Management is a solution introduced by Microsoft to Windows Server starting with 2012 which lets administrators manage their DHCP and DNS servers from a single console. Now that is a very simple explanation of the concept; IPAM can do a little more than just manage the servers like find available free addresses, view the address spaces from a single place, track an IP’s allocation by date and much more.

    This first post in the IPAM series will cover some basic topics regarding the product. In the next posts we will be installing it, configuring it and looking at some features. I am using Windows Server 2016 for the installation but most of the things are the same for 2012 and 2012 R2.
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Which CSS property is used to hide an element and will not affect the layout?

Which CSS property is used to hide an element and will not affect the layout?

  • visibility: hidden;
  • display: none;
  • display: false;
  • visibility: false; 
Which CSS property is used to hide an element and will not affect the layout?

EXPLANATION

<!DOCTYPE html>
<html>
<head>
<style>
h2.a {
  visibility: visible;
}

h2.b {
  visibility: hidden;
}
</style>
</head>
<body>

<h1>The visibility Property</h1>

<h2 class="a">This heading is visible</h2>

<h2 class="b">This heading is hidden</h2>

<p>Notice that the hidden heading still takes up space on the page.</p>

</body>
</html>

 Output

The visibility Property

This heading is visible

Notice that the hidden heading still takes up space on the page.


Source

https://www.w3schools.com/CSSref/tryit.asp?filename=trycss_visibility

 

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What event ID should you look for in Windows Logs - System to determine if your server has been shut down?

What event ID should you look for in Windows Logs - System to determine if your server has been shut down?

  • 44
  • 41
  • 12
  • 13 
What event ID should you look for in Windows Logs - System to determine if your server has been shut down?

EXPLANATION

The kernel power event ID 41 error occurs when the computer is shut down, or it restarts unexpectedly. When a computer that is running Windows starts, a check is performed to determine whether the computer was shut down cleanly. If the computer was not shut down cleanly, a Kernel Power Event 41 message is generated.

An event 41 is used to report that something unexpected happened that prevented Windows from shutting down correctly. There may be insufficient information to explicitly define what happened. To determine what may have happened and to identify a potential resolution, it is important to know what the computer was doing at the time just before the event occurred.

If event 41 is logged because power to the computer was interrupted, consider obtaining an uninterruptible power supply (UPS) such as a battery backup power supply. An underpowered or failing power supply may cause this behavior. For example, if you added RAM or additional devices or hard disks when this problem began, the power supply may cause the problem.


An event 41 can occur in the following scenarios.

Scenario 1: The computer restarts, and there is a Stop error BugcheckCode in the event data

When a Stop error occurs, the Stop error data is written in Event ID 41 as part of the additional event data. There may be the instances in which the Stop error code information cannot be written before the computer restarts or shuts down. Such instances are covered in scenario 3.


 Note
The BugcheckCode data in the event is written in decimal format instead of a more typical hexadecimal format. Therefore, the decimal value should be converted to a hexadecimal value.

If the Stop error BugcheckCode entry in the event ID data is not zero, you should convert the BugcheckCode value from decimal to hexadecimal. Most documentation on Stop error codes reference the code as a hexadecimal value instead of a decimal value. To do this, follow these steps:
  1. Click Start, and then type calc in the Search box.
  2. Click View, and then click Programmer.
  3. Make sure that the Dec option button is selected on the left side of calculator.
  4. Use the keyboard to enter the decimal value from the BugcheckCode value.
  5. Click the Hex option button on the left side of the calculator.

 

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What is SAP HANA?

What is SAP HANA?

  • An in SSD Database Management System
  • An in Disk Database Management System
  • An in Memory Database Management System
  • An in Cloud Database Management System
What is SAP HANA?

EXPLANATION

SAP HANA is an in-memory, column-oriented, relational database management system developed and marketed by SAP SE.
Its primary function as database server is to store and retrieve data as requested by the applications. In addition, it performs advanced analytics (predictive analytics, spatial data processing, text analytics, text search, streaming analytics, graph data processing) and includes ETL capabilities as well as an application server.

SOURCE

https://en.wikipedia.org/wiki/SAP_HANA
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Thursday, June 13, 2019

Apple is changing the default user shell to what replacement starting in macOS 10.15 Catalina?

Apple is changing the default user shell to what replacement starting in macOS 10.15 Catalina?

  • bash
  • tcsh
  • zsh
  • dash 

Apple is changing the default user shell to what replacement starting in macOS 10.15 Catalina?

EXPLANATION


Apple unveiled macOS Catalina yesterday with support for iPad apps and lots of new features, but a big change for developers and power users was missing from the on stage presentation. Starting with macOS Catalina, Macs will now use zsh as the default
login shell and interactive shell across the operating system. All newly created user accounts in macOS Catalina will use zsh by default. Bash will still be available, but Apple is signaling that developers should start moving to zsh on macOS Mojave or earlier in anticipation of bash eventually going away in macOS.
Apple hasn’t explained exactly why it’s making this change, but bash isn’t exactly a modern shell as it’s implemented in macOS, and a switch to something less aging makes a lot more sense for the company. Apple is stuck using version 3.2 of bash that has been licensed under GPLv2, as newer versions are licensed under GPLv3. Apple has kept clear of using GPLv3 packages in macOS as the license is generally more restrictive to companies like Apple that sign their own code and it includes explicit patent grants, too.
While a number of Mac developers have already moved on to even more modern shells like Fish, zsh is more compatible with Bourne shell (sh) and mostly compatible with bash. There’s a lot more flexible autocomplete with zsh, and if you’re interested in moving to zsh on macOS Mojave then there are plenty of helpful guides for getting the best terminal setup and getting used to zsh before bash is fully phased out.
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What is the maximum password length allowed in Office 365?

What is the maximum password length allowed in Office 365?

  • 12 characters
  • 32 characters
  • 24 characters
  • 16 characters 
What is the maximum password length allowed in Office 365?

EXPLANATION


Microsoft instead recommends:
  • An 8-character minimum password length (Azure AD/Office 365 has a maximum password length of 16 characters for cloud identities)
  • Remove character composition requirements (i.e. don't require combinations of uppercase, lowercase, numbers, special characters, etc)
  • No password expiration
  • Ban common passwords
  • Educate users to not re-use corporate passwords for other systems and apps
  • Enforce multi-factor authentication
  • Enable risk-based multi-factor authentication challenges

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What is the IEEE standard committee number for Ethernet

What is the IEEE standard committee number for Ethernet

  • 802.11
  • 802.10
  • 802.3
  • 802.1 
What is the IEEE standard committee number for Ethernet

EXPLANATION

 IEEE 802.3 is a working group and a collection of Institute of Electrical and Electronics Engineers (IEEE) standards produced by the working group defining the physical layer and data link layer's media access control (MAC) of wired Ethernet. This is generally a local area network (LAN) technology with some wide area network (WAN) applications. Physical connections are made between nodes and/or infrastructure devices (hubs, switches, routers) by various types of copper or fiber cable.

802.3 is a technology that supports the IEEE 802.1 network architecture.
802.3 also defines LAN access method using CSMA/CD.
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Which of the following is a valid MAC address?

Which of the following is a valid MAC address?

  • 193.165.2.1
  • 00:D0:59:09:07:51
  • 2007:0db8:85a3:0000:0000:8a2e:0470:7457
  • 00:D0:59 

EXPLANATION

 A media access control address of a device is a unique identifier assigned to a network interface controller for communications at the data link layer of a network segment. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet and Wi-Fi. In this context, MAC addresses are used in the medium access control protocol sublayer.

The MAC address is formed in accordance to the rules of the three numbering name spaces, which are managed by the Institute of Electrical and Electronic Engineers (IEEE). The format is six sets of two digits or characters, separated by hyphens. An example of a MAC address is 30-65-EC-6F-C4-58.
Some manufacturers, such as Dell, place a unique identifier in the MAC address, which is called the Organizationally Unique Identifier (OUI), and identifies the manufacturer. The OUIs of some well-known firms are:
  • Dell: 00-14-22,
  • Cisco: 00-40-96,
  • Nortel: 00-04-DC.

 

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Which of the following protocols doesn't require a connection?

Which of the following protocols doesn't require a connection?

  • UDP
  • THC
  • IP
  • TCP 

Which of the following protocols doesn't require a connection?

EXPLANATION

Tetrahydrocannabinol (THC) is one of at least 113 cannabinoids identified in cannabis. THC is the principal psychoactive constituent of cannabis. With chemical name (−)-trans-Δ⁹-tetrahydrocannabinol, the term THC also refers to cannabinoid isomers.
Like most pharmacologically-active secondary metabolites of plants, THC is a lipid found in cannabis,[9] assumed to be involved in the plant's self-defense, putatively against insect predation, ultraviolet light, and environmental stress.[10][11][12]
THC, along with its double bond isomers and their stereoisomers[13], is one of only three cannabinoids scheduled by the UN Convention on Psychotropic Substances (the other two are dimethylheptylpyran and parahexyl). It was listed under Schedule I in 1971, but reclassified to Schedule II in 1991 following a recommendation from the WHO. Based on subsequent studies, the WHO has recommended the reclassification to the less-stringent Schedule III.[14] Cannabis as a plant is scheduled by the Single Convention on Narcotic Drugs (Schedule I and IV). It is specifically still listed under Schedule I by US federal law[15] under the Controlled Substances Act for having "no accepted medical use" and "lack of accepted safety". However, dronabinol is a synthetic form of THC approved by the FDA as an appetite stimulant for people with AIDS and antiemetic for people receiving chemotherapy.[16] The pharmaceutical formulation dronabinol is an oily resin provided in capsules available by prescription in the United States, Canada, Germany, and New Zealand.

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VMWare files ending with the .VMX extension hold what kind of data?

VMWare files ending with the .VMX extension hold what kind of data?

  • VHD connection data for the VM
  • Type 2 data for the host to start the VM properly
  • Primary configuration file and settings for the VM
  • Virtual Machine Extension data for the VM 
VMWare files ending with the .VMX extension hold what kind of data?

EXPLANATION

The .vmx file is the primary configuration file for VMWare, storing the settings you selected using either the New Virtual Machine Wizard or the virtual machine settings editor.
If you created the virtual machine using an earlier version of VMware Workstation on a Linux host, this file may have a .cfg extension.

.vmx <vmname>.vmx This is the primary configuration file, which stores settings chosen in the New Virtual Machine Wizard or virtual machine settings editor. If you created the virtual machine under an earlier version of VMware Workstation on a Linux host, this file may have a .cfg extension

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Friday, June 7, 2019

What can you use the "route" command for?

What can you use the "route" command for?

  • To set a fixed number of hops a packet can make
  • To print the expected response time
  • To determine the transit delay of packets
  • To display and modify the routing table 

EXPLANATION

In computing, route is a command used to view and manipulate the IP routing table in both Unix-like and Microsoft Windows operating systems. Manual manipulation of the routing table is characteristic of static routing.
E:\Users\techlanda>route

Manipulates network routing tables.

ROUTE [-f] [-p] [-4|-6] command [destination]
                  [MASK netmask]  [gateway] [METRIC metric]  [IF interface]

  -f           Clears the routing tables of all gateway entries.  If this is
               used in conjunction with one of the commands, the tables are
               cleared prior to running the command.

  -p           When used with the ADD command, makes a route persistent across
               boots of the system. By default, routes are not preserved
               when the system is restarted. Ignored for all other commands,
               which always affect the appropriate persistent routes. This
               option is not supported in Windows 95.

  -4           Force using IPv4.

  -6           Force using IPv6.

  command      One of these:
                 PRINT     Prints  a route
                 ADD       Adds    a route
                 DELETE    Deletes a route
                 CHANGE    Modifies an existing route
  destination  Specifies the host.
  MASK         Specifies that the next parameter is the 'netmask' value.
  netmask      Specifies a subnet mask value for this route entry.
               If not specified, it defaults to 255.255.255.255.
  gateway      Specifies gateway.
  interface    the interface number for the specified route.
  METRIC       specifies the metric, ie. cost for the destination.

All symbolic names used for destination are looked up in the network database
file NETWORKS. The symbolic names for gateway are looked up in the host name
database file HOSTS.

If the command is PRINT or DELETE. Destination or gateway can be a wildcard,
(wildcard is specified as a star '*'), or the gateway argument may be omitted.

If Dest contains a * or ?, it is treated as a shell pattern, and only
matching destination routes are printed. The '*' matches any string,
and '?' matches any one char. Examples: 157.*.1, 157.*, 127.*, *224*.

Pattern match is only allowed in PRINT command.
Diagnostic Notes:
    Invalid MASK generates an error, that is when (DEST & MASK) != DEST.
    Example> route ADD 157.0.0.0 MASK 155.0.0.0 157.55.80.1 IF 1
             The route addition failed: The specified mask parameter is invalid.
 (Destination & Mask) != Destination.

Examples:

    > route PRINT
    > route PRINT -4
    > route PRINT -6
    > route PRINT 157*          .... Only prints those matching 157*

    > route ADD 157.0.0.0 MASK 255.0.0.0  157.55.80.1 METRIC 3 IF 2
             destination^      ^mask      ^gateway     metric^    ^
                                                         Interface^
      If IF is not given, it tries to find the best interface for a given
      gateway.
    > route ADD 3ffe::/32 3ffe::1

    > route CHANGE 157.0.0.0 MASK 255.0.0.0 157.55.80.5 METRIC 2 IF 2

      CHANGE is used to modify gateway and/or metric only.

    > route DELETE 157.0.0.0
    > route DELETE 3ffe::/32 
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Which option do you use with "ipconfig" to purge the DNS cache?

Which option do you use with "ipconfig" to purge the DNS cache?

  • /cleanup
  • /purgedns
  • /cachedump
  • /flushdns 
Which option do you use with "ipconfig" to purge the DNS cache?

 EXPLANATION

Flushing the DNS cache on Windows  is a very easy process. Due to system security permissions, you must ensure that you run the command prompt as an administrator user.

  1. Ensure that you're on the Windows Start Screen.
  2. Simply type cmd and the Windows search bar will appear on the right hand side with search results.
  3. Right click on Command Prompt and click Run as administrator
  4. Type in the command ipconfig /flushdns

Linux

If you are running the nscd Name Service Cache Daemon and wish to flush your DNS cache, then you will need to do the following.
  1. Open up a command terminal (either as root or run step 2 with sudo).
  2. Run the command /etc/init.d/nscd restart
 
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If i wanted to find the Windows 10 Spotlight Lock Screen Pictures... Where would you find them?

If i wanted to find the Windows 10 Spotlight Lock Screen Pictures... Where would you find them?

  • C:\Windows\Web\Wallpaper
  • C:\ProgramData\Microsoft\Windows\SystemData
  • C:\Windows\Web\Screen
  • C:\Users\[USERNAME]\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager\LocalState\Asset 

If i wanted to find the Windows 10 Spotlight Lock Screen Pictures... Where would you find them?

EXPLANATION

C:\Users\[USERNAME]\AppData\Local\Packages\Microsoft.Windows.ContentDeliveryManager\LocalState\Asset is the correct answer... given 100 characters to work with. Since the backgrounds are downloaded, stored and overwritten.. they are stored here.
C:\ProgramData\Microsoft\Windows\SystemData is where the lock screen can be changed or overwritten, given permission.
C:\Windows\Web\Screen is the location of the windows prelogin screen background.
And C:\Windows\Web\Wallpaper is where default windows 7 wallpapers for your desktop are saved.

SOURCE

https://www.laptopmag.com/articles/find-windows-10-lock-screen-pictures
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Thursday, June 6, 2019

Which type of authorization provides a mechanism to validate both sender and receiver?

Which type of authorization provides a mechanism to validate both sender and receiver?

  • Kerberos
  • Anonymous
  • RADIUS
  • TACACS 
Which type of authorization provides a mechanism to validate both sender and receiver?

EXPLANATION

Kerberos is a computer network authentication protocol that works on the basis of tickets to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner. The protocol was named after the character Kerberos from Greek mythology, the ferocious three-headed guard dog of Hades. Kerberos An access control system that was developed at MIT in the 1980s. Turned over to the IETF for standardization in 2003, it was designed to operate in both small companies and large enterprises with multiple domains and authentication servers.

 

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Which of these fire extinguishers is best for putting out burning wires?

Which of these fire extinguishers is best for putting out burning wires?

  • Carbon dioxide
  • Sodium chloride
  • Copper powder
  • Foam 

EXPLANATION

If a small and contained fire breaks out – for example, if an extension cord begins to smolder -- you could successfully douse it with baking soda. That's right: baking soda, just like the kind you use in the kitchen. Baking soda contains sodium bicarbonate, which just happens to be the substance contained in Class C fire extinguishers, which are best suited for electrical fires. Baking soda produces water, which will effectively cool and smother a small fire.
Class C fires involve electrical equipment, such as appliances, wiring, circuit breakers and outlets. Never use water to extinguish class C fires - the risk of electrical shock is far too great! Class C extinguishers do not have a numerical rating. The C classification means the extinguishing agent is non-conductive. Geometric symbol (blue circle)
CO2 extinguishers have an advantage over dry chemical extinguishers since they don't leave a harmful residue - a good choice for an electrical fire on a computer or other favorite electronic device such as a stereo or TV.

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If an organization takes a full backup every Sunday morning and a daily differential backup each morning, what is the fewest number of backups that need to be restored after a disaster on Friday?

If an organization takes a full backup every Sunday morning and a daily differential backup each morning, what is the fewest number of backups that need to be restored after a disaster on Friday?

  • 7
  • 6
  • 1
If an organization takes a full backup every Sunday morning and a daily differential backup each morning, what is the fewest number of backups that need to be restored after a disaster on Friday?

EXPLANATION

Your network uses the following backup strategy: full backups every Sunday night and Differential backups Monday through Saturday nights. Thursday morning the storage system fails. How many restore operations will you need to perform to recover all of the data?
Answer 2

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Which of the following algorithms is used by MD5?

Which of the following algorithms is used by MD5?

  • Block cipher algorithm
  • Asymmetric encryption algorithm
  • Cryptographic algorithm
  • Hashing algorithm 
Which of the following algorithms is used by MD5?

EXPLANATION

MD5 which stands for Message Digest algorithm 5 is a widely used cryptographic hash function that was invented by Ronald Rivest in 1991. The idea behind this algorithm is to take up a random data (text or binary) as an input and generate a fixed size “hash value” as the output. The input data can be of any size or length, but the output “hash value” size is always fixed.


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Which of the following settings provides the greatest level of wireless security?

Which of the following settings provides the greatest level of wireless security?

  • WEP-Shared
  • WEP-Cipher
  • WEP-Open
  • WEP-Closed 
Which of the following settings provides the greatest level of wireless security?

EXPLANATION

 WEP was developed for wireless networks and approved as a Wi-Fi security standard in September 1999. WEP was supposed to offer the same security level as wired networks, however there are a lot of well-known security issues in WEP, which is also easy to break and hard to configure.

Despite all the work that has been done to improve the WEP system it still is a highly vulnerable solution. Systems that rely on this protocol should be either upgraded or replaced in case security upgrade is not possible. WEP was officially abandoned by the Wi-Fi Alliance in 2004.

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What is the address size for IPv6 addresses?

What is the address size for IPv6 addresses?

  • 128 bit
  • 32 bit
  • 64 bit
  • 256 bit 
What is the address size for IPv6 addresses?

EXPLANATION

Internet Protocol version 6 is the most recent version of the Internet Protocol, the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet.
IPv6 addresses are 128-bit IP address written in hexadecimal and separated by colons. An example IPv6 address could be written like this: 3ffe:1900:4545:3:200:f8ff:fe21:67cf.

 

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Which of the following protocols runs on port 22 and protects the authenticity and confidentiality of the data in transit?

Which of the following protocols runs on port 22 and protects the authenticity and confidentiality of the data in transit?

  • FTP
  • SSL
  • SCP
  • DHCP 

Which of the following protocols runs on port 22 and protects the authenticity and confidentiality of the data in transit?

EXPLANATION

The SCP is a network protocol, based on the BSD RCP protocol,[4] which supports file transfers between hosts on a network. SCP uses Secure Shell (SSH) for data transfer and uses the same mechanisms for authentication, thereby ensuring the authenticity and confidentiality of the data in transit. A client can send (upload) files to a server, optionally including their basic attributes (permissions, timestamps). Clients can also request files or directories from a server (download). SCP runs over TCP port 22 by default. Like RCP, there is no RFC that defines the specifics of the protocol. 

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What type of architecture should you implement if you are setting up a web server that needs to be accessed by both internal employees and external customers?

What type of architecture should you implement if you are setting up a web server that needs to be accessed by both internal employees and external customers?

  • NAT
  • VLAN
  • VPN
  • DMZ

What type of architecture should you implement if you are setting up a web server that needs to be accessed by both internal employees and external customers?

EXPLANATION

 In computer security, a DMZ Network (sometimes referred to as a "demilitarized zone") functions as a subnetwork containing an organization's exposed, outward-facing services. It acts as the exposed point to an untrusted networks, commonly the Internet.

 
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You are the system administrator for an organization that has 50 devices. Which IPv4 internal address range should you use on the network?

You are the system administrator for an organization that has 50 devices. Which IPv4 internal address range should you use on the network?

  • 10.x.x.x
  • 192.168.x.x
  • 172.16.x.x
  • 172.31.x.x 
You are the system administrator for an organization that has 50 devices. Which IPv4 internal address range should you use on the network?

EXPLANATION

 IP address classesWith an IPv4 IP address, there are five classes of available IP ranges: Class A, Class B, Class C, Class D and Class E, while only A, B, and C are commonly used. Each class allows for a range of valid IP addresses, shown in the following table.

ClassAddress rangeSupports
Class A1.0.0.1 to 126.255.255.254Supports 16 million hosts on each of 127 networks.
Class B128.1.0.1 to 191.255.255.254Supports 65,000 hosts on each of 16,000 networks.
Class C192.0.1.1 to 223.255.254.254Supports 254 hosts on each of 2 million networks.
Class D224.0.0.0 to 239.255.255.255Reserved for multicast groups.
Class E240.0.0.0 to 254.255.255.254Reserved for future use, or research and development purposes.
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Which of the following is part of a database that holds only one piece of data?

Which of the following is part of a database that holds only one piece of data?

  • Field
  • Report
  • File
  • Record 
Which of the following is part of a database that holds only one piece of data?

EXPLANATION

In a database table, a field is a data structure for a single piece of data. Fields are organized into records, which contain all the information within the table relevant to a specific entity.


Field The basic unit of database tables that holds one piece of data, such as first name, last name etc.
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What is the transfer rate of a standard USB 2.0 Device?

What is the transfer rate of a standard USB 2.0 Device?

  • 250 Mbit/s
  • 480 Mbit/s
  • 100 Mbit/s
  • 1 Gbit/s 

What is the transfer rate of a standard USB 2.0 Device?

EXPLANATION

The now-aging USB 2.0 standard can theoretically transfer data at a very high 480 megabits per second (mbps), or 60 megabytes per second (MBps). That’s impressive, but not as much as the newer USB 3.0, which can handle up to 5gbps (640MBps)—over ten times as fast as the 2.0 maximum.

Release versions

Name Release date Maximum transfer rate Note
USB 0.7 November 11, 1994 ? Pre-release
USB 0.8 December 1994 ? Pre-release
USB 0.9 April 13, 1995 Full Speed (12 Mbit/s) Pre-release
USB 0.99 August 1995 ? Pre-release
USB 1.0-RC November 1995 ? Release Candidate
USB 1.0 January 15, 1996 Full Speed (12 Mbit/s), Low Speed (1.5 Mbit/s)
USB 1.1 August 1998 Full Speed (12 Mbit/s)[35]
USB 2.0 April 2000 High Speed (480 Mbit/s)
USB 3.0/3.1 Gen 1/3.2 Gen 1×1 November 2008 SuperSpeed USB (5 Gbit/s) Also referred to as USB 3.1 Gen 1[27] and USB 3.2 Gen 1×1
USB 3.1 Gen 2/3.2 Gen 2×1 July 2013 SuperSpeed USB 10Gbps (10 Gbit/s) Includes new USB 3.1 Gen 2[27] which is later also named USB 3.2 Gen 2×1
USB 3.2 Gen 1×2 August 2017 SuperSpeed USB 10Gbps (10 Gbit/s) Includes new USB 3.2 Gen 1×2
USB 3.2 Gen 2×2 August 2017 SuperSpeed USB 20Gbps (20 Gbit/s) Includes USB 3.2 Gen 2×2 multi-link modes[36][not in citation given]
USB 4 TBD Estimated TBA (40 Gbit/s)

SOURCE

https://www.pcworld.com/article/2360306/usb-3-0-speed-real-and-imagined.html
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What is the main function of BIOS?

What is the main function of BIOS?

  • To enable the graphics card
  • To load the operating system
  • To upgrade drivers
  • To enable the network card 
What is the main function of BIOS?

EXPLANATION

BIOS uses Flash memory, a type of ROM. The BIOS software has a number of different roles, but its most important role is to load the operating system.
When you turn on your computer and the microprocessor tries to execute its first instruction, it has to get that instruction from somewhere.

SOURCE

https://computer.howstuffworks.com/bios1.htm
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Wednesday, June 5, 2019

What is the intended range for a Class 1 Bluetooth transceiver?

What is the intended range for a Class 1 Bluetooth transceiver?

  • 33 meters
  • 100 meters
  • 500 meters
  • 10 meters 

EXPLANATION

  Range of Bluetooth is dependant on its class and primarily there are three classes of Bluetooth:


  •     Class 1 transmitting at 100 mW with a range of 100 meters or 328 feet.
  •     Class 2 transmiting at 2.5 mW with a range of 10 meters or 33 feet (most Bluetooth headsets and headphones are common Class 2 devices).
  •     Class 3 transmitting at 1 mW with a range of fewer than 10 meters.
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What is the purpose of an Exchange Autodiscover?

What is the purpose of an Exchange Autodiscover?

  • It is the Microsoft version of an MX record, which tells the interwebs where mail goes and stuff...
  • To pool then auto populate mail info into outlook.
  • allow exchange OWA to allow users easier login.
  • to establish initial connections to Exchange user mailboxes. 

What is the purpose of an Exchange Autodiscover?

EXPLANATION


Exchange Autodiscover is a web service that helps Microsoft Exchange administrators configure user profile settings for clients running Outlook 2007, Outlook 2010, or Outlook 2013 and mobile phones running Windows Mobile 6.1 or later.
Introduced in Exchange Server 2007, the primary purpose of the Exchange Autodiscover service is to establish initial connections to Exchange user mailboxes. Once


SOURCE

https://searchwindowsserver.techtarget.com/definition/Exchange-Autodiscover-service
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You wish to place a video on a webpage such that it will be playable directly in the browser. Which is the most suitable file type to use?

You wish to place a video on a webpage such that it will be playable directly in the browser. Which is the most suitable file type to use?

  • .rm (Realmedia)
  • .webm (WebM)
  • .flv (Adobe Flash)
  • .mov (Quicktime) 

 

EXPLANATION

Most modern browsers can play the .webm file format directly, without the need for any special plugins. Many can also play .mp4 (MPEG 4) or Ogg files directly, so that could also be an option. However, support for these is not as universal.
WebM is actually a subformat of the Matroska container, with video in VP8 or VP9  encoding, and audio in Vorbis. or Opus. VP8 and Vorbis will give the widest compatibility.
The older standards of Realmedia, Quicktime, and Flash Video required special plugins to be installed, and in some cases these plugins suffered numerous security vulnerabilities. Thus, their use is to be discouraged. 

Support for WebM on legacy hardware is good, provided that a modern browser is installed. MPEG 4 is less likely to work in browsers on older operating systems, although the free VLC Media Player can play the downloaded files if streaming is not possible.

https://fileinfo.com/extension/webm

SOURCE

https://developer.mozilla.org/en-US/docs/Web/HTML/Supported_media_formats
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