Tiểu luận môn mạng máy tính Electronic Mail: SMTP To explain the architecture of electronic mail using four scenarios. To explain the user agent (UA) Transfer Protocol (SMTP) as the formal protocol that handles MTA. To explain email transfer phases.
School of Electronics and Telecommunications 1/25 Presented by: Pham Van Chi Bui Thi The Ha Electronic Mail: SMTP School of Electronics and Telecommunications 2/25 OBJECTIVES: OBJECTIVES: To explain the architecture of electronic mail using four scenarios. To explain the user agent (UA) Transfer Protocol (SMTP) as the formal protocol that handles MTA. To explain e-mail transfer phases. School of Electronics and Telecommunications 3/25 Explain the architecture of electronic mail To explain the architecture of email, we give four scenarios To explain the architecture of email, we give four scenarios Scenarior 1 Scenarior 2 Scenarior 3 Scenarior 4 School of Electronics and Telecommunications 4/25 Figure 1 First scenario 1 2 School of Electronics and Telecommunications 5/25 When the sender and the receiver of an e- mail are on the same mail server, we need only two user agents. Note: Note: School of Electronics and Telecommunications 6/25 Figure 2 Second scenario 1 2 3 4 5 School of Electronics and Telecommunications 7/25 When the sender and the receiver of an e- mail are on different mail servers, we need two UAs and a pair of MTAs (client and server). Note: Note: School of Electronics and Telecommunications 8/25 Figure 3 Third scenario 1 2 3 4 5 6 7 School of Electronics and Telecommunications 9/25 When the sender is connected to the mail server via a LAN or a WAN, we need two UAs and two pairs of MTAs (client and server). Note: Note: School of Electronics and Telecommunications 10/25 Figure 4 Fourth scenario 1 2 3 4 5 6 8 9 [...]... School of Electronics and Telecommunications 14/25 Transfer Protocol (SMTP) - Để gửi mail, hệ thống phải có client MTA - Để nhận mail Hệ thống phải có server MTA - Giao thức định nghĩa MTA client và server trên Internet được gọi là SMTP (Simple Mail Transfer Protocol) ng ng - Scenario 4 là trườ hợp thườ gặp nhất - Hình 7 thể hiện phạm vi sử dụng giao thức SMTP trong scenario này School of Electronics... 15/25 Figure 7 SMTP range School of Electronics and Telecommunications 16/25 Figure 8 Commands and responses • command/response interaction – commands: ASCII text – response: status code and phrase • messages must be in 7-bit ASCII • Uses CRLF.CRLF to determine end of message School of Electronics and Telecommunications 17/25 School of Electronics and Telecommunications 18/25 School of Electronics and... transfer School of Electronics and Telecommunications 20/25 Figure 10 1 Connection termination QUIT 221 service closed School of Electronics and Telecommunications 2 21/25 Example Send A Fake Mail uses QK SMTP server -Sử dụng TELNET để login cổng 25 (the well-known port for SMTP) - Sử dụng câu lệnh để gửi email - Giả sử billg@microsoft.com gửi 1 email cho chipvc@gmail.com School of Electronics and Telecommunications... input From:Gates To:chipvc@gmail.com Date:Sat Jan 5,2008 9:45 PM Subject:Test to send fake email 23 School of Electronics and Telecommunications 23/25 Figure 11 SMTP, Pop3 and IMAP4 School of Electronics and Telecommunications 24/25 Any School of Electronics and Telecommunications 25/25 ... server) This is the most common situation today School of Electronics and Telecommunications 11/25 Figure 5 Push versus pull School of Electronics and Telecommunications 12/25 Explain the user agent (UA), u - UA là thành phần đầ tiên của một hệ thống thư điện tử i - Cung cấp dịch vụ tới ngườ sử dụng - Giúp quá trình gửi nhận thư dễ dàng hơn School of Electronics and Telecommunications 13/25 Figure 6 User... billg@microsoft.com gửi 1 email cho chipvc@gmail.com School of Electronics and Telecommunications 22/25 Example Continued ================== Connection Establishment ================ 220 Welcome to QK SMTP Server 3 helo hacker (Type helo & any name followed by space) 250 Hello hacker (Server Welcomes You) ===================== Envelope =================== MAIL FROM: billg@microsoft.com 250 billg@microsoft.com . Protocol (SMTP) - g i mail, h th ng ph i có client MTAĐể ử ệ ố ả - nh n mail. H th ng ph i có server MTAĐể ậ ệ ố ả - Giao th c nh ngh a MTA client và server trên Internet ứ đị ĩ c g i là SMTP (Simple. ặ ấ - Hình 7 th hi n ph m vi s d ng giao th c SMTP trong ể ệ ạ ử ụ ứ scenario này School of Electronics and Telecommunications 16/25 Figure 7 SMTP range School of Electronics and Telecommunications 17/25 Figure. Electronics and Telecommunications 1/25 Presented by: Pham Van Chi Bui Thi The Ha Electronic Mail: SMTP School of Electronics and Telecommunications 2/25 OBJECTIVES: OBJECTIVES: To explain the