1. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Chapter 22 Simple Mail Transfer Protocol (SMTP)

2. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 CONTENTS USER AGENT (UA) ADDRESSES DELAYED DELIVERY ALIASES MAIL TRANSFER AGENT (MTA) COMMANDS AND RESPONSES MAIL TRANSFER PHASES MIME MAIL DELIVERY MAIL ACCESS PROTOCOLS

3. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-1 SMTP concept

4. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-2 UAs and MTAs

5. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-3 Relay MTAs

6. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-4 Mail gateway

7. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 USER AGENT (UA) 22.1

8. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-5 Format

9. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 ADDRESSES 22.2

10. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-6 Address

11. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 DELAYED DELIVERY 22.3

12. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-7 Sender-site delay

13. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-8 Receiver-site delay

14. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 ALIASES 22.4

15. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-9 Alias expansion

16. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-10 One-to-many expansion

17. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-11 Many-to-one expansion

18. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 MAIL TRANSFER AGENT 22.5

19. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-12 Email system

20. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 COMMANDS AND RESPONSES 22.6

21. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-13 Commands and responses

22. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-14 Command format

23. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 MAIL TRANSFER PHASES 22.7

24. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-15 Connection establishment

25. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-16 Message transfer

26. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-17 Connection termination

27. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 MULTIPURPOSE INTERNET MAIL EXTENSIONS (MIME) 22.8

28. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-18 MIME

29. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-19 MIME header

30. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-20 Base64

31. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-21 Quoted-printable

32. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 MAIL DELIVERY 22.9

33. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-22 Email delivery

34. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 MAIL ACCESS PROTOCOLS 22.10

35. McGraw-Hill©The McGraw-Hill Companies, Inc., 2000 Figure 22-22 POP3