What CIDR Range is reserved for Network interconnectivity device benchmark testing?

What CIDR Range is reserved for Network interconnectivity device benchmark testing?

• 14.0.0.0/8
• 240.0.0.0/4
• 223.255.255.0/24
• 198.18.0.0/15 

 

EXPLANATION

198.18.0.0/15 - This block has been allocated for use in benchmark tests of network interconnect devices. [RFC2544] explains that this range was assigned to minimize the chance of conflict in case a  testing device were to be accidentally connected to part of the Internet. Packets with source addresses from this range are not meant to be forwarded across the Internet. 

Special address blocks

Address block	Address range	Number of addresses	Scope	Description
0.0.0.0/8	0.0.0.0–0.255.255.255	16777216	Software	Current network[3] (only valid as source address).
10.0.0.0/8	10.0.0.0–10.255.255.255	16777216	Private network	Used for local communications within a private network.[4]
100.64.0.0/10	100.64.0.0–100.127.255.255	4194304	Private network	Shared address space[5] for communications between a service provider and its subscribers when using a carrier-grade NAT.
127.0.0.0/8	127.0.0.0–127.255.255.255	16777216	Host	Used for loopback addresses to the local host.[3]
169.254.0.0/16	169.254.0.0–169.254.255.255	65536	Subnet	Used for link-local addresses[6] between two hosts on a single link when no IP address is otherwise specified, such as would have normally been retrieved from a DHCP server.
172.16.0.0/12	172.16.0.0–172.31.255.255	1048576	Private network	Used for local communications within a private network.[4]
192.0.0.0/24	192.0.0.0–192.0.0.255	256	Private network	IETF Protocol Assignments.[3]
192.0.2.0/24	192.0.2.0–192.0.2.255	256	Documentation	Assigned as TEST-NET-1, documentation and examples.[7]
192.88.99.0/24	192.88.99.0–192.88.99.255	256	Internet	Reserved.[8] Formerly used for IPv6 to IPv4 relay[9] (included IPv6 address block 2002::/16).
192.168.0.0/16	192.168.0.0–192.168.255.255	65536	Private network	Used for local communications within a private network.[4]
198.18.0.0/15	198.18.0.0–198.19.255.255	131072	Private network	Used for benchmark testing of inter-network communications between two separate subnets.[10]
198.51.100.0/24	198.51.100.0–198.51.100.255	256	Documentation	Assigned as TEST-NET-2, documentation and examples.[7]
203.0.113.0/24	203.0.113.0–203.0.113.255	256	Documentation	Assigned as TEST-NET-3, documentation and examples.[7]
224.0.0.0/4	224.0.0.0–239.255.255.255	268435456	Internet	In use for IP multicast.[11] (Former Class D network).
240.0.0.0/4	240.0.0.0–255.255.255.254	268435455	Internet	Reserved for future use.[12] (Former Class E network).
255.255.255.255/32	255.255.255.255	1	Subnet	Reserved for the "limited broadcast" destination address.[3][13]

 

 

SOURCE

https://tools.ietf.org/html/rfc2544

 

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In Windows PowerShell, which of the following is a way you can load WPF for the creation of GUI interfaces in your scripts?

In Windows PowerShell, which of the following is a way you can load WPF for the creation of GUI interfaces in your scripts?

• [reflection.assembly]::loadwithpartialname("System.Windows.Forms")
• Add-Assembly -AssemblyName System.Windows.Forms
• New-Object -TypeName System.Reflection.Assembly(System.Windows.Forms)
• New-Assembly -AssemblyName "WPF" 

 EXPLANATION

You would call the System.Reflection.Assembly object, then load the WPF assembly, "System.Windows.Forms" with the method LoadWithPartialName. This allows you to then add objects from the System.Windows.Forms assembly, like Form or Button.

SOURCE

https://msdn.microsoft.com/en-us/library/system.reflection.assembly.loadwithpartialname(v=vs.110).aspx

 

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What is the codenamed for the Microsoft Hyper-V?

What is the codenamed for the Microsoft Hyper-V?

• Viridian
• Vendana
• Victory
• Vicious 

 

EXPLANATION

Microsoft Hyper-V, codenamed Viridian and formerly known as Windows Server Virtualization, is a native hypervisor; it can create virtual machines on x86-64 systems running Windows. Starting with Windows 8, Hyper-V supersedes Windows Virtual PC as the hardware virtualization component of the client editions of Windows NT. A server computer running Hyper-V can be configured to expose individual virtual machines to one or more networks.

Hyper-V was first released alongside Windows Server 2008, and has been available without charge for all the Windows Server and some client operating systems since.

Hyper-V is also available on the Xbox One, in which it would launch both Xbox OS and Windows 10.

SOURCE

https://en.wikipedia.org/wiki/Hyper-V

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What do you do when you receive this error on a client machine "The trust relationship between this workstation and the primary domain failed"

What do you do when you receive this error on a client machine "The trust relationship between this workstation and the primary domain failed"

• Unplug the ethernet cable, power off and on, plug the ethernet cable back in and log in.
• Reboot the machine in "Safe Mode" and change the Administrator Password
• Log in as local Admin and rejoin the machine to the Domain
• Reboot the machine and keep hitting the F7 key until the machine connects with the Domain. 

 

EXPLANATION

When you try to access a computer running Windows that is a member of your domain and it fails... it will show this message:

"The trust relationship between this workstation and the primary domain failed"
The reason;

The computer's machine account has the incorrect role or its password has become mismatched with that of the domain database.

Trust relationship issue Microsoft

SOURCE

http://www.tomshardware.com/forum/28973-63-trust-relationship-workstation-primary-domain-failed

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What is the keyboard shortcut for locking a PC on Windows XP or later?

What is the keyboard shortcut for locking a PC on Windows XP or later?

• Win + L
• Ctrl + Alt + Del
• Win + S
• Win + D 

 

EXPLANATION

Windows is chock full of helpful and fast keyboard shortcuts. One area that many end users struggle with is properly securing their workstations when away from their desk. IT Professionals often overcome this through AFK timeouts in group policy, however it is always helpful to educate your users on ways to help them help themselves. Most users are familiar with using their mouse to navigate their start menu to the "Lock" option, and some more experienced users might still be using "Ctrl + Alt + Del," followed by either the spacebar, or a click of the "Lock" option, however "Win + L" is a quick and easy solution that most can remember when you remind them that they are "Locking" their "Windows" with a "Key." 

https://en.wikipedia.org/wiki/Windows_key#Windows_XP

 

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In PowerShell, which of the following expressions round a floating point number contained in the variable $Num to 2 decimal places?

In PowerShell, which of the following expressions round a floating point number contained in the variable $Num to 2 decimal places?

• Get-RoundNumber -Number $Num -Precision 2
• $Num -round 2
• $Num.Round(2)
• [Math]::Round($Num, 2) 

 

EXPLANATION

As of PowerShell version 5, there is no native PowerShell cmdlet to round numbers; additionally, floating point types do not contain a method to accomplish this.  The best way to round a number to a certain precision is to utilize the .NET framework's System.Math class, which contains the static method Round().

Technically, Math.Round() only accepts numbers of the type double or decimal, but passing it a float (also known as a single) will automatically convert that number to a double for this purpose.

The above example and solution uses the following definition of Round():

static double Round(double value, int digits)

Additional documentation on the System.Math.Round() method:https://msdn.microsoft.com/en-us/library/system.math.round(v=vs.110).aspx

 

 

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Which gnu/linux command lets you see the latest logged in users to your server ?

Which gnu/linux command lets you see the latest logged in users to your server ?

• sudo
• tcpdump
• last
• netstat 

 

EXPLANATION

https://www.centoshowtos.org/commands/last/

SOURCE

https://www.centoshowtos.org/commands/last/

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