If Windows cannot find an active DHCP server, which network does it use by default for the network port?

If Windows cannot find an active DHCP server, which network does it use by default for the network port?

• 192.168.0.0/16
• 169.254.0.0/16
• 172.16.0.0/12
• 127.0.0.1/32 

 

EXPLANATION

The 169.254.0.0/16 network is used for Automatic Private IP Addressing, or APIPA. If a DHCP client attempts to get an address, but fails to find a DHCP server after the timeout and retries period it will randomly assume an address from this network. This is defined in RFC 3927.
192.168.0.0/16 and 172.16.0.0/12 are defined for private use networks (LANs). It has to be configured by manual installation as a static IP or by a DHCP Server.
127.0.0.1/32 is the loopback address of the PC. The loopback address can be used to test the performance of TCP/IP by pinging 127.0.0.1. Upon receiving a response, you can assume that the software associated with the protocol is fine.

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In Microsoft SQL Server, why does SELECT 1/2 return 0?

In Microsoft SQL Server, why does SELECT 1/2 return 0?

• Numerator and denominator are both integers, so the result will be an integer
• It doesn't - it returns 0.5
• A bug in the code performing the division
• A bug in the display in SSMS 

 

EXPLANATION

Due to the data type of the numerator and denominator being an "int", the return type is also assigned as an integer. While internally, the engine performs the calculation as 0.5, because the data type is an integer, the value gets converted to 0 and is returned as such.
Another way to say this is that the mathematical answer is 0.5 but because the system is only able to return an integer (whole number) the answer becomes 0 (the "whole number" in the answer).

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Which of the following Windows console commands deletes a folder (c:\test), whether or not it is empty, without issuing any warnings?

Which of the following Windows console commands deletes a folder (c:\test), whether or not it is empty, without issuing any warnings?

• rd test
• rd test\* /q
• del c:\test\*.* /s
• rd c:\test /s /q 

EXPLANATION

The /s switch deletes ALL elements recursively inside the specified folder.
The /q switch is the silent mode, meaning there will be absolutely no warnings.

Caution

When you run rd /s in quiet mode, the entire directory tree is deleted without confirmation. Ensure that important files are moved or backed up before using the /q command-line option.

 

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What is the maximum number of devices that you can connect to a single USB 2.x controller?

What is the maximum number of devices that you can connect to a single USB 2.x controller?

• 255
• 31
• 63
• 127

EXPLANATION

Technically, a USB network is capable of supporting 128 nodes, though the USB controller itself is also a node.
In addition, any USB hubs, self-powered or bus-powered, count as additional nodes and reduce the number of nodes you can connect to the controller.
https://en.wikipedia.org/wiki/USB_hub#Physical_layout

 

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Which of the following is NOT a daemon in Postfix?

Which of the following is NOT a daemon in Postfix?

• qmgr
• master
•  crond
• smtpd 

 

EXPLANATION

The crond daemon is a Linux daemon, not a Postfix daemon.
The master daemon is the brain of the Postfix mail system. It spawns all other daemons. The smtpd daemon (server) handles incoming connections. The qmgr daemon is the heart of the Postfix mail system. It processes and controls all messages in the mail queues.

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