Lesson 1

 

Lesson Preview

In today lesson i’m going to talk about:

  • The differences between ASCII mode and Binary Mode
  • Defining the terms: FTP, HTTP, FTPS, HTTPS, SSL, Compression / Decompression, Encryption / Decryption
  • Explaining the differences between Active mode & Passive mode

Research Q&A

Explain the differences between:ASCII mode & Binary mode

ASCII, otherwise known as American Standard Code for Information Interchange, is a set of 128 symbols that any computer in the world can display.  Any file that is made up of text or text-based components, such as an HTML file, text file, or PostScript file, is an ASCII file. These include:

  • .htm .html .shtml .php .pl .cgi .js .cnf .css
  • .htaccess .map .pwd .txt .grp .ctl

Binary files, on the other hand, are structured differently (e.g. 011001), and therefore require a different style of transfer. Images, applications, and generated archive/cabinet files such as .zip and .tar files are all binary file types. These include:

  • .jpg .gif .png .tif .exe .zip .sit .rar .ace
  • .class .mid .ra .avi .ocx .wav .mp3 .au
  • .doc, .xls, .fla, .swf

Both ASCII and binary files can be sent in binary mode with no problems, but sending a binary file in ASCII mode will corrupt the binary file’s structure.  If in doubt, transfer in binary mode.
(ref. http://knowledge.3essentials.com/web-hosting/article/1619/FTP-basics-what-is-binary-vs-ascii-mode.html)

Define terms: FTP, HTTP, FTPS, HTTPS, SSL, Compression / Decompression, Encryption / Decryption

FTP stands for File Transfer Protocol (FTP), and is a standard network protocol used to transfer computer files between a client and server on a computer network.
(ref. https://en.wikipedia.org/wiki/File_Transfer_Protocol)

HTTPS (also called HTTP over TLS, HTTP over SSL, and HTTP Secure) is a protocol which consists of communication over HTTP within a connection encrypted by Transport Layer Security or its predecessor, Secure Sockets Layer.
(ref. https://en.wikipedia.org/wiki/HTTPS)

Compression is decreasing a file’s size, through removing redundant information.
(ref. http://searchstorage.techtarget.com/definition/compression)

Decompression restores the compressed file to its original file size.
(ref. https://www.techopedia.com/definition/14330/decompression)

Encryption uses a mathematical formula to encrypt a file to make the data unreadable without the decrypting key
(ref. https://en.wikipedia.org/wiki/Encryption)

Explain the differences between: Active mode & Passive mode

In the active mode, the client starts listening on a random port for incoming data connections from the server (the client sends the FTP command PORT to inform the server on which port it is listening)..

In the passive mode, the client uses the control connection to send a PASV command to the server and then receives a server IP address and server port number from the server, which the client then uses to open a data connection to the server IP address and server port number received.
(ref. https://southrivertech.com/what-is-the-difference-between-active-and-passive-ftp/ )

Conclusion

Let’s review our lesson today.

  • We have now know what the difference between ACSII (known as American Standard Code for Information Interchange, is a set of 128 symbols that any computer in the world can display) and Binary files(are structured differently (e.g. 011001)).
  • We now know what the terms FTP ,HTTPS, Compression /Decompression, Encryption / Decryption means.
  • We now know what the difference between Passive and Active mode is.