What is FTP?

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What is File Transfer Protocol (FTP)?

FTP, File Transfer Protocol, is a protocol through which internet users can upload files from their computers to a website or download files from a website to their PCs. Originated by Abhay Bhushan in 1971 for use in the military and scientific research network known as ARPANET, FTP has evolved into a protocol for far wider applications on the World Wide Web with numerous revisions throughout the years.

FTP is the easiest way to transfer files between computers via the internet, and utilizes TCP, transmission control protocol, and IP, internet protocol, systems to perform uploading and downloading tasks.

How It Works

TCP and IP are the two major protocols that keep the internet running smoothly. TCP manages data transfer while IP directs traffic to internet addresses. FTP is an underling of TCP and shuttles files back and forth between FTP server and FTP client. Because FTP requires that two ports be open–the server’s and the client’s–it facilitates the exchange of large files of information.

First, you as client make a TCP control connection to the FTP server’s port 21 which will remain open during the transfer process. In response, the FTP server opens a second connection that is the data connection from the server’s port 20 to your computer.

Using the standard active mode of FTP, your computer communicates the port number where it will stand by to receive information from the controller and the IP address–internet location–from which or to which you want files to be transferred.

If you are using a public–or anonymous–FTP server, you will not need proprietary sign-in information to make a file transfer, but you may be asked to enter your email address. If you are using a private FTP server, however, you must sign in with a user name and password to initiate the exchange of data.

Modes of File Transfer

Three modes of transferring data are available via FTP. The system can use a stream mode, in which it transfers files as a continuous stream from port to port with no intervention or processing of information into different formats. For example, in a transfer of data between two computers with identical operating systems, FTP does not need to modify the files.

In block mode, FTP divides the data to be transferred into blocks of information, each with a header, byte count, and data field. In the third mode of transfer, the compressed mode, FTP compresses the files by encoding them. Often these modifications of data are necessary for successful transfer because the file sender and file receiver do not have compatible data storage systems.

Passive FTP

Should your computer have firewall protection, you may have difficulties using FTP. A firewall protects your PC by preventing internet sites from initiating file transfers. You can circumvent your firewall’s function by using the PASV command that reverses the FTP process, allowing your computer to initiate the transfer request.

Many corporate networks use PASV FTP as a security measure to protect their internal network from assaults of unwanted external files. Also called passive FTP, the process requires that any transfer of information from the internet or other external source must be initiated by the client or private network rather than the external source.

Further FTP Security

In response to the need for a more secure transfer process for sensitive information such as financial data, Netscape developed a Secure Sockets Layer (SSL) protocol in 1994 that it used primarily to secure HTTP–HyperText Transfer Protocol–transmissions from tampering and eavesdropping. The industry subsequently applied this security protocol to FTP transfers, developing SFTP, a file transfer protocol armored with SSL for protection from hackers.

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IPv6

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Internet Protokol Version 6 (Türkçe: Internet Protokol sürüm 6) kısaca IPv6, 32 bitlik bir adres yapısına sahip olan IPv4’ün adreslemede artık yetersiz kalması ve ciddi sıkıntılar meydana getirmesi üzerine geliştirilmiştir.

IPv4 oluşturulmaya başlandığında İnternet’in bu kadar ilerleyeceği hesap edilmemişti. Şimdi adresleme sıkıntısı oluşunca 128 bitlik adres yapısı olan IPv6’ya geçilmesi kaçınılmaz olmuştur. Bu sefer gelecek fazlasıyla düşünülerek oluşturulmuş bir adres yapısıdır. Yeni adreslemede sınırsız denebilecek bir adres aralığı olacaktır.

IPv6’da olan trafik işgal edici paket başlıkları kaldırılarak bir hız arttırımına gidilmiştir. Ayrıca yeni eklenen şifreleme sistemleriyle daha güvenli iletimler sağlanmaktadır. Uçlar arasında şifreli iletimi kolaylaştıran AH ve ESP başlıkları mevcuttur. AH ve ESP başlıkları uçlar arasındaki tüm veri iletimini şifreleyen IPSec protokolünü desteklemek amaçlı kullanılmıştır.

Ayrıca şu anda IPv4’ün, QoS eklentisiyle idare ettiği ama tam olarak destekleyemediği görüntü ve ses iletimi sıkıntısı IPv6 ile çözülecektir. IPv6, görüntü ve ses paketlerine “öncelikli pakettir” ibaresi atanarak bunlara trafikte öncelik tanımasına olanak sağlamaktadır.

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What is SMTP?

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What is Simple Mail Transfer Protocol (SMTP)?

SMTP stands for Simple Mail Transfer Protocol. It’s a set of communication guidelines that allow software to transmit email over the Internet. Most email software is designed to use SMTP for communication purposes when sending email, and It only works for outgoing messages. When people set up their email programs, they will typically have to give the address of their Internet service provider’s SMTP server for outgoing mail. There are two other protocols – POP3 and IMAP – that are used for retrieving and storing email.

SMTP provides a set of codes that simplify the communication of email messages between servers. It’s a kind of shorthand that allows a server to break up different parts of a message into categories the other server can understand. Any email message has a sender, a recipient – or sometimes multiple recipients – a message body, and usually a title heading. From the perspective of users, when they write an email message, they see the slick interface of their email software, but once that message goes out on the Internet, everything is turned into strings of text. This text is separated by code words or numbers that identify the purpose of each section. SMTP provides those codes, and email server software is designed to understand what they mean.

The other purpose of SMTP is to set up communication rules between servers. For example, servers have a way of identifying themselves and announcing what kind of communication they are trying to perform. There are also ways to handle errors, including common things like incorrect email addresses. In a typical SMTP transaction, a server will identify itself, and announce the kind of operation it is trying to perform. The other server will authorize the operation, and the message will be sent. If the recipient address is wrong, or if there is some other problem, the receiving server may reply with an error message of some kind.

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What is SSL?

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What is a Secured Socket Layer (SSL)?

A Secured Socket Layer, or SSL, is the usual way that a website creates a secure connection with a web browser. Whenever a web surfer visits a secure site that uses SSL technology, it creates an encrypted link between their browser session and the web server. SSL is the industry standard for secure web communication and is used to protect millions of online transactions each day.

What Does Encryption Mean?

Encryption simply means that the information that is going back and forth between an individual’s computer and the website is scrambled so that no one else can understand it. A formula on each side is used to scramble the information before sending it and unscramble it upon receipt. If a hacker happens to intercept the personal information en route, it would be worthless to them.

What is a SSL Certificate?

The web server must have an SSL certificate before it can create an SSL connection. When someone activates SSL protocols on their web server, they are asked to answer questions that will establish their identity. The questions ask for information about both the website and the company. After the SSL certificate is requested, the web server creates two cryptographic keys, one is a Private Key and the other is a Public Key. These keys are used along with the encryption formula to create the secure link between the web server and browser sessions.

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What is a Mail Server?

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With the click of a mouse button, you can send an email from one point of the globe to another in a matter of seconds. Most of us take this process for granted, giving little thought to how it actually works. It’s easy to understand how standard snail-mail gets from point A to point B – but how does an email message make its way from a sender to a recipient? The answer to that question revolves around something called a mail server. You can learn more about the role that mail serves play in email delivery by reading on below.

What is a Mail Server?

A mail server is the computerized equivalent of your friendly neighborhood mailman. Every email that is sent passes through a series of mail servers along its way to its intended recipient. Although it may seem like a message is sent instantly – zipping from one PC to another in the blink of an eye – the reality is that a complex series of transfers takes place. Without this series of mail servers, you would only be able to send emails to people whose email address domains matched your own – i.e., you could only send messages from one example.com account to another example.com account.

Types of Mail Servers

Mail servers can be broken down into two main categories: outgoing mail servers and incoming mail servers. Outgoing mail servers are known as SMTP, or Simple Mail Transfer Protocol, servers. Incoming mail servers come in two main varieties. POP3, or Post Office Protocol, version 3, servers are best known for storing sent and received messages on PCs’ local hard drives. IMAP, or Internet Message Access Protocol, servers always store copies of messages on servers. Most POP3 servers can store messages on servers, too, which is a lot more convenient.

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What is VOIP?

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“VOIP – Short for Voice Over Internet Protocol, a category of hardware and software that enables people to use the Internet as the transmission medium for telephone calls by sending voice data in packets using IP rather than by traditional circuit transmissions…” (quoted from Webopedia Computer Dictionary).

Uses

VOIP has become a growing method of communication in the modern world, especially in sales-oriented jobs. It has been integrated mostly for business purposes to replace conventional phone calls. The methods of use can be classified into three major categories:

  • To interconnect VOIP phones within a single building using the building’s Local Area Network (LAN)
  • To interconnect VOIP phones between multiple locations of the same organization using a backbone network
  • To interconnect VOIP phones to regular telephones in different organizations or for sales purposes

Benefits

Toll-Free Calls

The main purpose of VOIP is to provide a method of cheap yet extensive communication. Regular telephone calls can become costly if used too frequently, yet with VOIP one only needs to pay for a good internet connection and subscription to a VOIP service. With these two facilities handy, VOIP becomes a capability to make limitless phone calls through the internet. Although the person at the other end may be using a regular phone, the VOIP user either uses a computer or VOIP phone to communicate.

The major advantage of VOIP is that it allows the user to make as many phone calls as they like for a fixed price instead of being charged by the minute. This makes a huge cutback on costs for jobs such as telephone marketing that require making many phone calls for hours every day.

VOIP can become low-cost or toll-free for people who are using only the internet to communicate. If both or all users are using the internet to communicate, VOIP becomes a way of talking or conferencing without having to pay any additional fee apart from the regular fee for internet.

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What is an IP Address?

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No doubt you’ve heard the term “IP address.” Unless you’re a techie, though, you may not have more than a shadowy notion of what an IP address actually is or how it works. Let’s explore the concept.

An IP address is a fascinating product of modern computer technology designed to allow one computer (or other digital device) to communicate with another via the Internet. IP addresses allow the location of literally billions of digital devices that are connected to the Internet to be pinpointed and differentiated from other devices. In the same sense that someone needs your mailing address to send you a letter, a remote computer needs your IP address to communicate with your computer.

“IP” stands for Internet Protocol, so an IP address is an Internet Protocol address. What does that mean? An Internet Protocol is a set of rules that govern Internet activity and facilitate completion of a variety of actions on the World Wide Web. Therefore an Internet Protocol address is part of the systematically laid out interconnected grid that governs online communication by identifying both initiating devices and various Internet destinations, thereby making two-way communication possible.

An IP address consists of four numbers, each of which contains one to three digits, with a single dot (.) separating each number or set of digits. Each of the four numbers can range from 0 to 255. Here’s an example of what an IP address might look like: 78.125.0.209. This innocuous-looking group of four numbers is the key that empowers you and me to send and retrieve data over our Internet connections, ensuring that our messages, as well as our requests for data and the data we’ve requested, will reach their correct Internet destinations. Without this numeric protocol, sending and receiving data over the World Wide Web would be impossible.

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What is a Web Server?

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Many people know how to drive a car, but have little or no knowledge about how the car actually works. So, too, are many people familiar with how to view and navigate web pages, but have limited knowledge of how those web pages do what they do. Here we will answer the question: “What is a web server?”

At the most basic level, a web server is simply a computer program that dispenses web pages as they are requested. The machine the program runs on is usually also called a server, and the two references are interchangeable in everyday conversation. When someone sits down at a computer and enters an address into an internet browser like Internet Explorer or Firefox, the browser sends a request off into the internet asking to view the web page found at that address. The web server is the program or machine that responds to that request, and delivers the content of the page back to the user.

This can be done because every computer or device that connects to the internet has a uniquely identifying number, called an Internet Protocol address, or IP address for short. This address is what allows computers to find one another and communicate across the network. In brief, the process works as follows.

Every web page on the internet also has a unique address, called a Uniform Resource Locator, or URL. Something like “www.example.com/page1.htm” is an example of a typical URL. When a user types that URL into a web browser, the machine the browser is running on sends a request to the IP address of the machine running the web server for that page, requesting that all the content found there be sent back. Once the web server receives that request, it sends the page content back to the IP address of the computer asking for it. The web browser then translates that content into all of the text, pictures, links, videos, etc. that so many web pages contain.

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What is a POP3?

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POP3, which is an abbreviation for Post Office Protocol 3, is the third version of a widespread method of receiving email. Much like the physical version of a post office clerk, POP3 receives and holds email for an individual until they pick it up. And, much as the post office does not make copies of the mail it receives, in previous versions of POP3, when an individual downloaded email from the server into their email program, there were no more copies of the email on the server; POP automatically deleted them.

POP3 makes it easy for anyone to check their email from any computer in the world, provided they have configured their email program properly to work with the protocol.

Mail Server Functionality

POP3 has become increasingly sophisticated so that some administrators can configure the protocol to “store” email on the server for a certain period of time, which would allow an individual to download it as many times as they wished within that given time frame. However, this method is not practical for the vast majority of email recipients.

While mail servers can use alternate protocol retrieval programs, such as IMAP, POP3 is extremely common among most mail servers because of its simplicity and high rate of success. Although the newer version of POP offers more “features,” at its basic level, POP3 is preferred because it does the job with a minimum of errors.

Working With Email Applications

Because POP3 is a basic method of storing and retrieving email, it can work with virtually any email program, as long as the email program is configured to host the protocol. Many popular email programs, including Eudora and Microsoft Outlook, are automatically designed to work with POP3. Each POP3 mail server has a different address, which is usually provided to an individual by their web hosting company. This address must be entered into the email program in order for the program to connect effectively with the protocol. Generally, most email applications use the 110 port to connect to POP3. Those individuals who are configuring their email program to receive POP3 email will also need to input their username and password in order to successfully receive email.

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What is W3C Browser Geolocation?

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W3C Browser Geolocation

If you’ve looked at an iPod, iPhone or other smartphone, if you’ve used the Firefox, Chrome or Opera browsers, or if you’ve used Google in the past couple years, you’ve probably seen something that points out your location. Indeed, Google has long been able to target local results to your searches based on where you are in the world – geolocation technology is behind the increased push toward localized search. The web is becoming local, as it is increasingly the case that people want to use the Internet not to reach far afield, but to deepen their understanding of their own backyards.

How W3C Geolocation Works

W3C Geolocation is the World Wide Web Consortium’s attempt to standardize this technology for use in any web-related application for a client-side device. Standardization isn’t as easy as it seems, as geolocation isn’t so much about a single program as it is a collection of several disparate programs, each of which provides an imperfect solution to the problem. The imperfections in each solution overlap with the geolocation capacities of the others, so the combination is a sort of perfect basket that allows for any computer connected to the Internet to find where it’s located. The technologies used are: IP Geolocation, GPS, Wi-Fi Positioning and Cell Tower Triangulation. Each technology adds a level of certainty to W3C geolocation.

IP Geolocation

IP Geolocation is easily implemented into a website, but it suffers from limitations of specificity. Each IP block corresponds roughly to a geographical area, so you can usually figure out what city someone is in. However, it often produces false positives, and the data should be checked against other forms of geolocation.

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