Design and Management of Email Service Source : homepage.ntu.edu.tw/~jsc/2005-mail.ppt Outline Introduction to the architecture and operation of SMTP Design of a suitable email system – Webmail solutions Postfix and simple configuration samples Spam and virus filtering Conclusion 2 Overview Electronic mail service has already evolved into one of the major Internet applications. It is not only fundamental, but also a must. Users may become impatient when mails were delayed, not to mention failed to access their emails. – Imagine we meet the situation of power failure or cut of water supply 3 Architecture of a Simple Mail System Consists of the following components – MTA - Mail transfer agent Sending and forwarding emails Server end – MDA - Mail delivery agent Delivering emails to recipients’ mailbox Server end – Pop3/Imap4 Daemons For users to download their mailboxs Server end – MUA - Mail user agent Reading and composing emails 4 Client end Architecture of a Simple Mail System Protocols Used for Mail System Protocols – For computer programs to communicate with each other – Similar to languages that human beings speak SMTP – Simple Mail Transfer Protocol – Too simple to provide any “advanced features” Authentication Authorization POP3 – Post Office Protocol version 3 – Simple IMAP4 – Internet Message Access Protocol version 4 – Fully compatible with internet message standards, e.g. MIME. – Allow messages to be accessed from more than one computer. – Provide support for online, offline, and disconnected modes. 6 – Multiple and share folders. Mail Forwarding Between Servers How to Find the Way to the Destination? How do we find the way to
[email protected]? 8 DNS: The Key to All Internet Services Query DNS server by the address part of email address.(
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