SMTP (Simple Mail Transfer Protocol)

Vladimir V. Riabov, Rivier College

Introduction

SMTP Fundamentals

SMTP Model and Protocol

User Agent

Sending e-Mail

Mail Header Format

Receiving e-Mail

The SMTP Destination Address

Delayed Delivery

Aliases

Mail Transfer Agent

SMTP Mail Transaction Flow

SMTP Commands

Mail Service Types

SMTP Service Extensions

SMTP Responses

SMTP Server

On-Demand Mail Relay

Multipurpose Internet Mail Extensions (MIME)

MIME-Version

Content-Type

Content-Transfer-Encoding

Content-Id

Content-Description

Security Scheme for MIME

Mail Transmission Types

Mail Access Modes

Mail Access Protocols

POP3

IMAP4

SMTP Security Issues

SMTP Vulnerabilities

SMTP Server Buffer Overflow Vulnerability

Mail Relaying SMTP Vulnerability

Mail Relaying SMTP Vulnerability in Microsoft Windows 2000

Encapsulated SMTP Address Vulnerability

Malformed Request Denial of Service

Extended Verb Request Handling Flaw

Reverse DNS Response Buffer Overflow

Firewall SMTP Filtering Vulnerability

Spoofing

Bounce Attack

Restricting Access to an Outgoing Mail Server

Mail Encryption

Bastille Hardening System

POP and IMAP Vulnerabilities

Standards, Organizations, and Associations

Internet Assigned Numbers Authority

Internet Engineering Task Force Working Groups

Internet Mail Consortium

Mitre Corporation

Conclusion

Glossary

Cross References

References

Further Reading

INTRODUCTION

Electronic mail (e-mail) is one of the most popular network services nowadays. Most e-mail systems that send mail over the Internet ...

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