sshhhhhhh. Lets talk about this fancy little term called "ssh". What exactly is ssh and what does it do? ssh stands for Secure Shell, and it is essentially a protocol used in order for two devices to talk to each other or communicate with each other. It is called "secure shell" because this protocol uses strong encryption to allow safe communication between a client and a server. So for example, you can basically connect to a computer (server) remotely by using this protocol. It is used for logging into computers over the internet, and to communicate with them (execute commands) to transfer data (such as files, or important information)--although this is just one function out of many other uses!! Every time you "ssh" into something, you are accessing that computer/server over the network. You can connect to a server via a particular terminal (like Terminal in macOS, PuTTY..etc.) and the SSH protocol!! The procedures usually vary from terminal to terminal but if you type in ssh into any particular terminal, it should give you a list of options (flags) you can use to connect to a server. These options or flags specify certain restrictions that the protocol needs to apply. For example the ssh -4 options enables ssh to use only IPv4 addresses. The -6 flag uses IPv6 addresses. The -i flag tells ssh that there is an "identity file" (such as a private key) which authenticates the user to communicate with the server. How does it work??When you establish a connection to a remote server, by using the ssh protocol (typing the command into the terminal and setting the destination server host name), there are 2 steps that help the client/server verify and prove their identity to each other. The client needs to make sure its accessing the right ssh server, therefore, when the client initiates a connection with the server, the server verifies its identity to the client. Then, the user/client verifies that they are authorized to access the server (User authentication). This is obviously a very high level approach of understanding ssh, there are many many tiny details the ssh protocol involves (such as public key authentication). I'll get into that more on later, but for now, GOOD LUCK :)
1 Comment
Fun fact: Today is the first palindrome date in 909 years: 02/02/2020! The Internet is such a powerful force; it allows us to communicate/recieve information from different parts of the world! It's just insane and amazing to visualize the different aspects of networking; and how the Internet forever revolutionized our way of seeking information! It all has to do with the hyped up term "Internet of Things". The term Internet of Things, or IoT, describes a system of connected devices, appliances, vehicles and digital technologies (and other "things") that can send data/information without human-to-human or human-to-device interactions. So instead of me walking up to another individual/device in another country to send some info, I can do that using the Internet. WiFi vs. InternetI have always used the words WiFi and Internet interchangeably, you don't even know so many times! But there is a slight difference between these terms. WiFi essentially stands for "wireless networks", and the Internet is "interconnected networks". There was a point in time where devices could only be connected through cables to connect from one device to another. It wasn't too efficient, however, since there was a location limit, and it was kinda inconvenient if you wanted to connect more devices. So essentially what WiFi does is it allows you to connect with devices without cables, in a local area network (like your homes, for example). It does this by using a router, which routes information (in small packets of info) from one device to another. The wireless local network is completely separate from the Internet. The Internet is a wide area network, or WAN. It is a huge network which links devices and computers across the world. How is the information transmitted?So first off, every device on the Internet has some sort of unique identifier, for devices to recognize one another. This is called an IP address. Our laptops, phones, and servers (which are devices that manage/store information) have IP addresses. So how are these vast amounts of devices all connected globally, around the world? Well first off, this is a simple diagram of two devices are connected to the Internet: Both of these devices will have unique IP addresses, and the Internet is basically the vast networks which data packets will route to until its destination is reached. So when you send information from your device to another device, the information is split into packets and is routed to the destination device via the Internet. But how exactly does this all work, and that to wirelessly? The computer needs to process the message, convert the text to signals, send it to the Internet, and the router near device 2 needs to convert the signals back into text. For this to be accomplished, there needs to be a protocol stack. Every device needs this, and this usually is in its operating system. Server being downWhen you are accessing a website, you are basically sending a HTTP protocol command to the web server in the Internet, to transmit the webpage (that's why websites start with http!!) Now you know when you were trying to access a website, and for some reason your web browser isn't processing the request. It often happens when the web server is down and under maintenance. These are some examples of when the server might be facing a technical problem: Gateway time-out occurs when web server is communicating fast enough with other servers to process your request. Networking and the Internet is just a whole new world; there is so much more to explore!
When storing data on the "cloud" became a super big thing, I never really understood what the "cloud" meant. Was it just a supercomputer which handled massive amounts of data from companies, individuals, and other entities? Or was it more than that? The term 'cloud computing' refers to the ability to offer many services--such as storing data, servers, networking, and intelligence--over the cloud or Internet. Cloud Computing is literally one of the most BIGGEST services ever. Many companies, such as the Amazon Web Services (AWS) and Microsoft Azure offer cloud computing support mainly in order to handle and store data, and offer software applications. but first, what is the cloud?Before diving deep into cloud computing, we should first learn about what cloud is. What does the term "cloud" refer to? It would be really cute if it were an actual cloud lol, but its actually not. I know, the term is very misleading. The cloud is essentially a bunch or "network" of servers. What does this mean? A server is a computer device which stores data, and offers support for other software programs or devices called clients. An example of a cloud service is Office 365 or Google Drive. So whenever you are storing your data or information in a cloud service, you are storing it in the cloud, which basically leads to storing it in a physical server. So this is how communication between a client (aka your device, or applications in your device) and a server occurs. It is known as the client-server model. big data and cloud computingNow, we know that data is all around us. For companies, every day, and every second of the day, some amount of data is generated. There is basically too much data to handle. So many companies have too much data to handle and store. This is known as big data. How do you store large amounts of data, and how can you handle, cleanse and protect it? These companies can store it in their own data centers or servers, but it requires a lot of effort and cost. Cloud Computing services can take care of all of that. AWS and Azure are just a few of the services offered to protect, handle, and store data from other companies or individuals. So essentially, other companies would buy the service, and pay per month, for the cloud computing service to store, handle, and protect the company's data in their servers. These are just some of the few services offered from AWS and Azure. There are many more. potential risks in cloud computingNow, all of this sounds very good. Companies with vast amounts of data can go to a cloud computing service and purchase their plan in order to store all of their data in the service's servers. However, there are some potential risks. Privacy is a huge concern for these companies. They are basically trusting the cloud computing services to protect their data and not leaking it to other competitors and companies. There will defintely be mutual agreements about privacy between the companies and the services. But, privacy is still a concern, and the data in the servers and in the "cloud" needs to be secure, protected and monitored. Even though there are a few risks, cloud computing makes accessing data much faster and efficient. It is a great technological lead for this industry.
What are IP addresses? and what are they used for? If you type in "ipconfig" on your command prompt in Windows, you can see your current IPv4 address of your device. But how does all of this work? Every device on a network has a certain unique address or identifier. This address is used to send data to other computers in a network, and is known as an IP address (Internet Protocol). There are two different standards for IP addresses: IPv4 and IPv6. The IPv6 format is a newer system, and many computers are also starting to use the IPv6 format as well. The main difference between these two standards is that the IPv4 address uses 32 bits to represent a unique address and IPv6 uses 128 bits to represent a unique address on the network. IPv4 Address The IPv4 address is represented by 4 numbers (that are 8 bit binary) so anything between 0.0.0.0 to 255.255.255.255. Although, there are some address that are meant for other purposes in the IP networks. For example, the 0.0.0.0 address represents an unknown target or a default network. 255.255.255.255 address is a broadcast address; it sends a broadcast packet to all of the computers in a particular network. The address 127.0.0.1 is called the loopback address so that the computer knows how to identify itself, regardless of having an IP address. Computer Networking Now that we know more about IP addresses, lets talk about the Networking Basics! Computers were connected to each other to form a network using a cable called Ethernet. Ethernet can transport lots of data. In order to successfully build a good network, people used network hubs. A network hub is where the Ethernet cables from every computer are connected to a device (hub). So, if computer 1 wants to send a message to another computer, it first has to send it to the hub (through the Ethernet cable), and then the hub sends it to all the other connected computers. This way may not be too efficient and may slow things down if 2 or 3 of these computers were sending messages at the same time. To make this efficient, these networks uses switches to send messages to the intended computer. So if Computer 1 wants to send a message only to Computer 4, the switch will be enabled so that the message doesn't unnecessarily reach the other computers in the network, and only Computer 4.
However, if a message needs to be sent to a device in another network, a router will need to be used. A router is essentially a networking device that can transfer data between networks, and it facilitates the exchange of data packets via the Internet. When a data packet comes from a data line (that the router is connected to), the router reads the address of the packet and determines where its destination is. It then directs the packet to the next network to reach the destination. |
Archives
March 2021
Topics
All
|