I came across a very interesting blog(cloudflare) where subnet is defined so easily. I am not modifying content here but putting same content so that i don’t miss this content.

A subnet, or subnetwork, is a network inside a network. Subnets make networks more efficient. Through subnetting, network traffic can travel a shorter distance without passing through unnecessary routers to reach its destination.

Imagine Alice puts a letter in the mail that is addressed to Bob, who lives in the town right next to hers. For the letter to reach Bob as quickly as possible, it should be delivered right…

VPN is a virtual private network connection over a public-access network, such as the Internet.

A VPN has three primary goals.

  1. Privacy — Communicating parties want to make sure that no one else can read or see their communication. VPN products typically use encryption to address privacy.
  2. Integrity — a guarantee that the data arrives exactly as the sender intended (i.e., no one tampered with the message in transit). VPN products typically use an agreed-upon public-key private-key pair to address integrity.
  3. Authenticity — a confirmation that the sender and receiver are who they say they are. …

Network Security Group (NSG):

A NSG filters traffic at the network layer from and to Azure VNet and consists of security rules that allows or denies traffic based on 5-tuple information:
1. Protocol — such as TCP, UDP, ICMP
2. Source — IP address,
3. Source port
4. Destination
5. Destination port

You can associate an NSG with a subnet or the network interface of an Azure VM. In accordance with Best practices, it’s recommended to scope NSGs at the subnet level or network interface, not both. This can make it complicated when having to troubleshoot network issues

Application Security…

Virtual Networking

A local area network, or LAN, is a kind of wired network that can usually only reach within the domain of a single building. A wide area network, or WAN, is another kind of wired network, but the computers and devices connected to the network can stretch over a half-mile in some cases.

Conversely, a virtual network doesn’t follow the conventional rules of networking because it isn’t wired at all. Therefore, all devices that interact with each other in the network do so through internet technology, allowing them to have a further reach than they would have if they were…

After reading multiple blogs found good explanation on Microsoft blogs only

VMs have many benefits. These include the ability to run different operating systems on the same server, more efficient and cost-effective utilisation of physical resources and faster server provisioning. On the flip side, each VM contains an OS image, libraries, applications and more and therefore can become quite large.

A container virtualises the underlying OS and causes the containerised app to perceive that it has the OS — including CPU, memory, file storage and network connections — all to itself. Because the differences in underlying OS and infrastructure…

Cloud resources, of course, are still physical devices located somewhere on planet Earth. So even though your resources are stored in the cloud, you will still have to choose where they will be used. Selecting your Region and Availability Zone are about the first option when setting up any cloud resource.


A Zone is a single logical datacenter with its own power, network, and cooling resources. The Zone’s power, network, and cooling resources are independent of any nearby or collaborating Zones. One or more buildings may provide the physical space for the Zone’s compute and storage devices, however all…

What is new in Junit5 as compare to Junit4

  • Junit4 framework was contained in a single jar library. The whole library needs to be imported even when only a particular feature is required. In JUnit 5, we get more granularity and can import only what is necessary
  • One test runner can only execute tests in JUnit 4 at a time . JUnit 5 allows multiple runners to work simultaneously
  • JUnit 4 never advanced beyond Java 7, missing out on a lot of features from Java 8. JUnit 5 makes good use of Java 8 features

Package/modules of Junit 5

In Kotlin context we can also use sealed classes combined with whenexpression. Allowing compiler to verify all branch statements, making the statement else unnecessary.

This is one of the trending topics in interview questions. Here I am describing step-by-step discussion for cracking such design questions.

Basics Principle Of Scheduler

It will schedule a Job which will be triggered at a specified time.

Interview design question always comes in one-line requirement. The candidate has to gather complete requirement by asking questions.

In Below discussion, we have to find out the Use Case of Scheduler because interview and candidate might be having a different perception of the same question so let’s begin.

  1. Candidate: Can we set a repetitive task by this scheduler?

Interviewer: Yes

2. Candidate…

Suppose a sequence of numbers is arithmetic (that is, it increases or decreases by a constant amount each term), and you want to find the sum of the first nn terms.

Denote this partial sum by SnSn . Then

Sn=n(a1+an)2Sn=n(a1 + an)2 ,
where nn is the number of terms, a1a1 is the first term and anan is the last term.

The sum of the first nn terms of an arithmetic sequence is called an arithmetic series .

Example 1:

Find the sum of the first 2020 terms of the arithmetic series if a1=5a1=5 and a20=62a20=62 .

S20=20(5+62)2S20=670S20=20(5 + 62)2S20=670

kapil sharma

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