Lesson 11: Explaining Network Applications Flashcards
Define http
Application layer protocol that eables clients to request resources from an http server over tcp port 80 or for secure transmission https over tcp port 443
What is HTML
HyperText Markup Language (HTML) are plan text files coded with tags describing how the page to be formatted
How does HTTP allow clients to submit data to a server?
HTTP POST mechanism
What are the purpose of cookies?
Text file that preserves client session information
Define Transport Layer Security (TLS)
Security protocol that uses certificates for web authentication and encryption to protect web transmissions and other protocols
What layer of the OSI model does SSL and TLS work at?
Layer 5; Session layer
How does HTTPs work?
By implementing certificates from a 3rd party CA; the server generates a private key to decrypt information encrypted by the public key; the public key is available to anyone that interacts with the server
Define File Transfer Protocol (FTP)
Application protocol used to transfer files between hosts over port 20 and 21; SFTP, TFTP, etc
How is a FTP connection made?
An FTP client connects to control port (port 21) on the FTP server to transfer commands and status information
What are the two data transfer modes in a FTP connection?
Active mode or passive mode
How does active FTP operate/function?
Client sends PORT command to server control port 21, and the server responds by opening the data connection between the client port and TCP port 20
How does passive FTP function?
Clients sends PASV command to FTP server control port 21, the server responds by opening a random high port number and sends it to the client using the PORT command, which the client uses to initiate connection to the given port
Define TFTP (Trivial File Transfer Protocol)
Using UDP port 69, TFTP is only suitable for small files and only supports reading (GET)/writing (PUT) files
What Secure File Transfer Protocol (SFTP)?
SFTP; uses a SSH tunnel over port 22 to encrypt authentication and data transfer between client and server
What is required for SFTP?
An SSH server that supports SFTP and SFTP client software