HTTP SMTP POP IMAP DNS DHCP FTP SMB

Hypertext Transfer Protocol (HTTP)
-Protocols that are designed for common uses such as web browsing and email .
-When a web address or Uniform Resource Locator ( URL)is typed into a web browser ,the web browser establishes a connection to the web service .
-HTTP is a request /response protocol .
-The three common message types are GET ,POST ( formdata ),and PUT (upload).
-For secure communication across the Internet ,the HTTP Secure ( HTTPS)protocol is used .HTTPS uses authentication and encryption to secure data as it travels between the client and server .

Network Service
Simple Mail Transfer Protocol (SMTP)
transfers mailreliably and efficienty. SMTP message formats require amessage header and a message bod. When a clientsends email, the client SMTP process connects with aserver SMTP process on well-known port 25.

Post Office Protocol (POP)
enables a workstation toretrieve mail from a mail server. With POP, mail isdownloaded from the server to the client and then，deleted on the server. The server starts the POP serviceby passively listening on TCP port 110 for client connection requests.

Internet Message Access Protocol (IMAP)
is another protocol that describes a method to retrieve email messages .However ,unlike POP ,when the user connects to an IMAP -capable server ,copies of the messages are downloaded to the client application .
The original messages are kept on the server until manually deleted .Users view copies of the messages in their email client software .

Domain Name System (DNS)
It was created for domain name to address resolution for these network DNS uses a distributed set of servers to resovled the name associated with these numbered addresses.

Dynamic Host Configuration Protocol (DHCP)
The service enables devices on a network to obtain IP addresses and other information from a DHCP server.
This service automates the assignment of IP addresses,subnet masks, gateway, and other IP networking,parameters.

File Transfer Protocol (FTP)
is another commonly used application layer protocol. FTP was developed to allow for data transfer between a client and a server.
An FTP client is an application which runs on a computer that is being used to push and pull data. from an FTP server

Server Message Block (SMB)
is a client/server file sharing protocol to describe the structure of shares network resources, such as directories, file, printer, and serial ports. It is a request-respond protocol.
SMB message can:
~Start, authenticate, and terminate sessions
~Control file and printer access
~Allow an application to send or receive message to or from another device