- The port number used by the file transfer protocol FTP is 21
SMTP 25
HTTP 80
Receiving mail protocol POP3 110 - The host in the Internet should register the corresponding relationship between domain name and IP address in (authoritative domain name server)
- The function of editing, receiving and reading e-mails in the Internet is the user agent program
- Generic top-level domain name gTLD: The earliest top-level domain name is com, net, org, edu, gov, mil, int
- Use dots to separate the punctuation of the domain name
- Internet domain names are managed uniformly by DNS
- English letters in the domain name are not case sensitive
- Internet domain name server types include: root domain name server, top-level domain name server, authoritative domain name server and intermediate domain name server
- The service provided to Internet users using the SMTP protocol is (email)
- The domain name space of the Internet uses a tree structure
- The protocol used by the browser to access the hypertext information on the Web server is HTTP
- The protocol used to transfer web pages between the www browser and the www server is HTTP
- Sending mail usually uses SMTP protocol, and receiving mail usually uses POP3 protocol
- WWW uses a client/server working model
- Internet transmission address is composed of IP address and host port number
- The Hypertext Transfer Protocol HTTP identifies the resource to be operated by URL.
- Top-level domains are divided into national top-level domains, generic top-level domains and infrastructure domains
- The format of the user's E-mail address is: username@host domain name
- Briefly describe the connection process of the post office protocol POP3. When the
user reads the mail in the mailbox, the POP3 client in the user agent first requests the POP3 server to establish a TCP connection. After the TCP connection is successfully established, the user agent interacts with the POP3 server based on the pop3 protocol. Operations on the mailbox - Briefly describe the process of simple mail transfer protocol SMTP sending mail
(1) The SMTP client first actively requests to establish a TCP connection with the SMTP server
(2) After the TCP connection is successfully established, the server sends a message to respond to the client's connection request
(3) The client sends to the server The HELLO command is used to identify the sender, and the server responds to complete the handshake.
(4) The client uses the MAIL FROM and RCRT TO commands to notify the server of the sender and receiver of the mail.
(5) Uses the DATA command to notify the server that the server is ready to send the content of the mail .
(6) The client sends CRLF.CRLF to the server to notify the server that the mail is sent, and the SMTP enters the closing stage.
(7) The client sends a QUIT command to the server to notify the server that there is no mail to continue transmission, and requests to end the SMTP call and close the TCP connection
(8) In response to the QUIT command, the server sends a response, agrees to end the SMTP session, and disconnects the TCP connection - Computer network applications can be divided into several types of application architectures? What are the characteristics of various application types?
(1) Client/Server (C/S) structure: communication is only carried out between the client and the server, and there is no direct communication between the client and the client
(2) Pure P2P structure: there is no traditional server running all the time, all communication is It is the communication between peer-to-peer communication parties. The communication parties do not have the distinction between client and server in the traditional sense. The status is peer-to-peer.
(3) Hybrid structure: Combines C/S applications and P2P applications, and has a central server. Existence and direct communication between peers (clients) - What is non-persistent HTTP? What is non-pipelined persistent HTTP? What is pipelined persistent HTTP? Briefly describe the interaction process.
Non-persistent HTTP: refers to the HTTP client and HTTP server establishing a TCP connection and sending HTTP requests through the connection Message, receive HTTP response message, and then disconnect.
Non-pipeline persistent HTTP is also called non-pipeline persistent connection. After receiving the previous response message through the persistent connection, the client can send out the next object
Persistent HTTP in request message pipelining mode is also called pipe mode persistent connection. Before receiving the response message of the previous object through the persistent connection, the client continuously sends request messages to subsequent objects in turn, and then passes through the connection in turn. Receive the response message sent back by the server.
Guarantee for your future!
The boyfriend can’t make the girlfriend angry. The girlfriend is angry because the boyfriend is wrong. In any case, the boyfriend is wrong. If the boyfriend is wrong, he must willingly accept any punishment from the girlfriend, otherwise he will be matched with the girlfriend boyfriend. Just spit on Han, the boyfriend should make his girlfriend more happy and think more about his girlfriend, know how to pity and cherish his girlfriend, and take care of his girlfriend. To be continued. . . .