Academic Tutorials



English | French | Portugese | German | Italian
Home Advertise Payments Recommended Websites Interview Questions FAQs
News Source Codes E-Books Downloads Jobs Web Hosting
Chats

TCP/IP Tutorial
TCP/IP Introduction
TCP/IP Addressing
TCP/IP Protocols
What is TCP/IP ?
HTTP and HTTPS protocols
MIME and IMAP protocols
SSL and SMTP protocols
POP and FTP protocols
NTP and DHCP protocols
SNMP and LDAP protocols
ICMP and ARP protocols
RARP,BOOTP and PPTP protocols
TCP/IP email

HTML Tutorials
HTML Tutorial
XHTML Tutorial
CSS Tutorial
TCP/IP Tutorial
CSS 1.0
CSS 2.0
HLML
XML Tutorials
XML Tutorial
XSL Tutorial
XSLT Tutorial
DTD Tutorial
Schema Tutorial
XForms Tutorial
XSL-FO Tutorial
XML DOM Tutorial
XLink Tutorial
XQuery Tutorial
XPath Tutorial
XPointer Tutorial
RDF Tutorial
SOAP Tutorial
WSDL Tutorial
RSS Tutorial
WAP Tutorial
Web Services Tutorial
Browser Scripting
JavaScript Tutorial
VBScript Tutorial
DHTML Tutorial
HTML DOM Tutorial
WMLScript Tutorial
E4X Tutorial
Server Scripting
ASP Tutorial
PERL Tutorial
SQL Tutorial
ADO Tutorial
CVS
Python
Apple Script
PL/SQL Tutorial
SQL Server
PHP
.NET (dotnet)
Microsoft.Net
ASP.Net
.Net Mobile
C# : C Sharp
ADO.NET
VB.NET
VC++
Multimedia
SVG Tutorial
Flash Tutorial
Media Tutorial
SMIL Tutorial
Photoshop Tutorial
Gimp Tutorial
Matlab
Gnuplot Programming
GIF Animation Tutorial
Scientific Visualization Tutorial
Graphics
Web Building
Web Browsers
Web Hosting
W3C Tutorial
Web Building
Web Quality
Web Semantic
Web Careers
Weblogic Tutorial
SEO
Web Site Hosting
Domain Name
Java Tutorials
Java Tutorial
JSP Tutorial
Servlets Tutorial
Struts Tutorial
EJB Tutorial
JMS Tutorial
JMX Tutorial
Eclipse
J2ME
JBOSS
Programming Langauges
C Tutorial
C++ Tutorial
Visual Basic Tutorial
Data Structures Using C
Cobol
Assembly Language
Mainframe
Forth Programming
Lisp Programming
Pascal
Delphi
Fortran
OOPs
Data Warehousing
CGI Programming
Emacs Tutorial
Gnome
ILU
Soft Skills
Communication Skills
Time Management
Project Management
Team Work
Leadership Skills
Corporate Communication
Negotiation Skills
Database Tutorials
Oracle
MySQL
Operating System
BSD
Symbian
Unix
Internet
IP-Masquerading
IPC
MIDI
Software Testing
Testing
Firewalls
SAP Module
ERP
ABAP
Business Warehousing
SAP Basis
Material Management
Sales & Distribution
Human Resource
Netweaver
Customer Relationship Management
Production and Planning
Networking Programming
Corba Tutorial
Networking Tutorial
Microsoft Office
Microsoft Word
Microsoft Outlook
Microsoft PowerPoint
Microsoft Publisher
Microsoft Excel
Microsoft Front Page
Microsoft InfoPath
Microsoft Access
Accounting
Financial Accounting
Managerial Accounting
Network Sites


SSL and SMTP protocols

Previoushome Next




Secure Socket Layer(SSL)

  • To ensure security of data transported and routed through HTTP, LDAP or POP3 application layers,the SSL protocol was originally developed by Netscape. SSL is designed to make use of TCP as a communication layer to provide a reliable end-to-end secure and authenticated connection between two points over a network (for example between the service client and the server).


  • A D V E R T I S E M E N T
  • Notwithstanding this SSL can be used for protection of data in transit in situations related to any network service and it is used mostly in HTTP server and client applications.



  • Today, almost each available HTTP server can support an SSL session, whilst Netscape Navigator or IE browsers are provided with SSL-enabled client software.




Objectives of SSL

  1. Authenticating the client and server to each other:

    to authenticate the communicating parties to each other,the SSL protocol supports the use of standard key cryptographic techniques (public key encryption). Though the most frequent application consists in authenticating the service client on the basis of a certificate and SSL may also use the same methods to authenticate the client.

  2. Ensuring data integrity:

    during a session, data cannot be either unintentionally or intentionally tampered with.

  3. Securing data privacy:

    data in transport between the server and the client must be protected from interception and be readable only by the intended recipient. This prerequisite is necessary for both the data associated with the protocol itself (securing traffic during negotiations) and the application data that is sent during the session itself and SSL is in fact not a single protocol but rather a set of protocols that can additionally be further divided in two layers:

  4. <

    b>the protocol to ensure data security and integrity:

    this layer is composed of SSL Record Protocol

  5. the protocols that are designed to establish an SSL connection:

    three protocols are used in this layer: the SSL Handshake Protocol,the SSL Alert Protocol and the SSL ChangeCipher SpecPprotocol.




The SSL protocol stack is illustrated in the following figure:

To address the tasks as described above,SSL uses these protocols. The SSL record protocol is responsible for data integrity and encryption. As can be seen in above figure, it is also used to encapsulate data sent by other SSL protocols, and therefore, it is also involved in the tasks associated with the SSL check data. The other three protocols cover the areas of session management, cryptographic parameter management and transfer of SSL messages between the client and the server and prior to going into a more detailed discussion of the role of individual protocols and their functions let us describe two fundamental concepts related to the use of SSL.




The following figure illustrate the creation of a packet under SSL record protocol

  1. The SSL Record protocol

    To transfer any data within a session - both messages and other SSL protocols (for example the handshake protocol), as well as for any application data,the SSL record protocol is used.

  2. The Alert Protocol

    The Alert Protocol is used by parties to convey session messages associated with data functioning and exchange of the protocol. Each message in the alert protocol consists of two bytes and the first byte always takes a value, “warning” (1) or “fatal” (2) , that determines the severity of the message sent. Sending a message having a „fatal” status by either party will result in an immediate termination of the SSL session. The next byte of the message contains one of the defined error code, which may occur during an SSL communication session.

  3. The ChangeCipher Spec protocol

    This protocol is the simplest SSL protocol. It consists of a single message that carries the value of 1. The sole purpose of this message is to cause the pending session state to be established as a fixed state, which results, for example, in defining the used set of protocols. This type of message must be sent by the client to the server and vice versa. After exchange of messages, the session state is considered agreed. This message and any other SSL messages are transferred using the SSL record protocol.

  4. The handshake protocol

    The handshake protocol constitutes the most complex part of the SSL protocol and it is used to initiate a session between the server and the client. Within the message of this protocol, various components such as keys and algorithms used for data encryption are negotiated. Due to this protocol, it is possible to authenticate the parties to each other and negotiate appropriate parameters of the session between them. The process of negotiations between the server and the client is illustrated in the above figure. It can be divided into 4 phases separated with horizontal broken lines and during the first phase, a logical connection must be initiated between the client and the server followed by the negotiation on the connection parameters. The client sends the server a client_hello message containing data such as:

  5. Version:
    which is the highest SSL version supported by the client

  6. Random:
    which specifies data consisting of a 32-bit timestamp and 28 bytes of randomly generated data. This data is used to protect the key exchange session between the parties of the connection.

  7. Session ID:
    which specifies a number that defines the session identifier. A nonzero value of this field indicates that the client wishes to update the parameters of an existing connection or establish a new connection on this session. A zero value in this field indicates that the client wishes to establish a new connection.

  8. CipherSuite:
    which specifies a list of encryption algorithms and key exchange method supported by the client.




SMTP(Simple Mail Transfer Protocol)

  • SMTP or Simple Mail Transfer Protocol is a way to transfer email efficiently and reliably.



  • SMTP is a relatively simple and text-based protocol, where one or more recipients of a message are specified (and in most cases verified to exist) and then the message text is transferred.



  • To communicate among themselves,you can think of SMTP as the language that mail servers use it.




  • The SMTP Model

    The exchange of mail using TCP/IP is performed by a message transfer agent (MTA) and users normally don?t deal with the MTA. To set up the local MTA,the system administrator is responsible. The SMTP protocol describes how two In the Internet Protocol stack,MTAs communicate with each other using the single TCP connection. The SMTP standard is one of the most widely used upper layer protocols ans as its name implies, it is a protocol that defines how to transmit messages (mail) between two users. SMTP uses the concept of spooling and the idea of spooling is to allow mail to be sent from a local application to the SMTP application, which stores the mail in some device or memory. Once the mail has arrived at the spool, it has been queued. A server checks to see if any messages are available and then attempts to deliver them and if the user is not available for delivery, the server may try later. Eventually, if the mail cannot be delivered, it will be discarded or perhaps returned to the sender. This is known as an end-to-end delivery system, because the server is attempting to contact the destination to deliver, and it will keep the mail in the spool for the a period of time until it has been delivered. SMTP is found in the two RFCs. RFC 822 describes the structure for the message, which includes the envelope as well and RFC 821 specifies the protocol that controls the exchange of mail between two machines.

    The figure below illustrates a general model of SMTP.




    SMTP Commands

    1. The MAIL command identifies the originator of message.



    2. The next command, RCPT, identifies the recipient and more than one RCPT command can be issued if there are multiple recipients.



    3. The contents of the mail message are sent by the client using the DATA command and the final command, QUIT, terminates the mail exchange.


    4. Those were the commands used in the above examples, but SMTP has a few more commands:

    5. The RSET command causes both ends to reset and aborts the current mail transaction. Any stored information about sender and recipients or mail data is discarded.



    6. The VRFY command lets the client ask the sender to verify a recipients address, without sending mail to the recipient and it's often used by a system administrator, by hand, for debugging mail delivery problems.



    7. The NOOP command does nothing besides force the server to respond with an OK with a reply code (200).



    8. EXPN expands a mailing list, and is often used by the system administrator and similar to VRFY.



    9. The TURN command lets the server and client switch roles, to send mail in the reverse direction, without having to take down the TCP connection and create a new one.



    10. Three more commands are available but rarely implemented: SEND,SAML, and SOML. They replace the MAIL command and allow combinations of the mail being delivered directly to the users terminal (if logged in), or sent to the recipient?s mailbox.



    11. For further detailed information about SMTP commands look at the extensive look at SMTP command.





    Be the first one to comment on this page.




      TCP/IP Tutorial eBooks

    No eBooks on TCP/IP could be found as of now.

     
     TCP/IP Tutorial FAQs
    More Links » »
     
     TCP/IP Tutorial Interview Questions
    More Links » »
     
     TCP/IP Tutorial Articles

    No TCP/IP Articles could be found as of now.

     
     TCP/IP Tutorial News

    No News on TCP/IP could be found as of now.

     
     TCP/IP Tutorial Jobs

    No TCP/IP Articles could be found as of now.


    Share And Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages.
    • blinkbits
    • BlinkList
    • blogmarks
    • co.mments
    • connotea
    • del.icio.us
    • De.lirio.us
    • digg
    • Fark
    • feedmelinks
    • Furl
    • LinkaGoGo
    • Ma.gnolia
    • NewsVine
    • Netvouz
    • RawSugar
    • Reddit
    • scuttle
    • Shadows
    • Simpy
    • Smarking
    • Spurl
    • TailRank
    • Wists
    • YahooMyWeb

    Previoushome Next

    Keywords: SSL and SMTP protocols, yahoo mail smtp, outlook express smtp, smtp mail server, active directory ssl, smtp mail servers, setting up smtp, smtp set up, smtp email account

    HTML Quizzes
    HTML Quiz
    XHTML Quiz
    CSS Quiz
    TCP/IP Quiz
    CSS 1.0 Quiz
    CSS 2.0 Quiz
    HLML Quiz
    XML Quizzes
    XML Quiz
    XSL Quiz
    XSLT Quiz
    DTD Quiz
    Schema Quiz
    XForms Quiz
    XSL-FO Quiz
    XML DOM Quiz
    XLink Quiz
    XQuery Quiz
    XPath Quiz
    XPointer Quiz
    RDF Quiz
    SOAP Quiz
    WSDL Quiz
    RSS Quiz
    WAP Quiz
    Web Services Quiz
    Browser Scripting Quizzes
    JavaScript Quiz
    VBScript Quiz
    DHTML Quiz
    HTML DOM Quiz
    WMLScript Quiz
    E4X Quiz
    Server Scripting Quizzes
    ASP Quiz
    PERL Quiz
    SQL Quiz
    ADO Quiz
    CVS Quiz
    Python Quiz
    Apple Script Quiz
    PL/SQL Quiz
    SQL Server Quiz
    PHP Quiz
    .NET (dotnet) Quizzes
    Microsoft.Net Quiz
    ASP.Net Quiz
    .Net Mobile Quiz
    C# : C Sharp Quiz
    ADO.NET Quiz
    VB.NET Quiz
    VC++ Quiz
    Multimedia Quizzes
    SVG Quiz
    Flash Quiz
    Media Quiz
    SMIL Quiz
    Photoshop Quiz
    Gimp Quiz
    Matlab Quiz
    Gnuplot Programming Quiz
    GIF Animation Quiz
    Scientific Visualization Quiz
    Graphics Quiz
    Web Building Quizzes
    Web Browsers Quiz
    Web Hosting Quiz
    W3C Quiz
    Web Building Quiz
    Web Quality Quiz
    Web Semantic Quiz
    Web Careers Quiz
    Weblogic Quiz
    SEO Quiz
    Web Site Hosting Quiz
    Domain Name Quiz
    Java Quizzes
    Java Quiz
    JSP Quiz
    Servlets Quiz
    Struts Quiz
    EJB Quiz
    JMS Quiz
    JMX Quiz
    Eclipse Quiz
    J2ME Quiz
    JBOSS Quiz
    Programming Langauges Quizzes
    C Quiz
    C++ Quiz
    Visual Basic Quiz
    Data Structures Using C Quiz
    Cobol Quiz
    Assembly Language Quiz
    Mainframe Quiz
    Forth Programming Quiz
    Lisp Programming Quiz
    Pascal Quiz
    Delphi Quiz
    Fortran Quiz
    OOPs Quiz
    Data Warehousing Quiz
    CGI Programming Quiz
    Emacs Quiz
    Gnome Quiz
    ILU Quiz
    Soft Skills Quizzes
    Communication Skills Quiz
    Time Management Quiz
    Project Management Quiz
    Team Work Quiz
    Leadership Skills Quiz
    Corporate Communication Quiz
    Negotiation Skills Quiz
    Database Quizzes
    Oracle Quiz
    MySQL Quiz
    Operating System Quizzes
    BSD Quiz
    Symbian Quiz
    Unix Quiz
    Internet Quiz
    IP-Masquerading Quiz
    IPC Quiz
    MIDI Quiz
    Software Testing Quizzes
    Testing Quiz
    Firewalls Quiz
    SAP Module Quizzes
    ERP Quiz
    ABAP Quiz
    Business Warehousing Quiz
    SAP Basis Quiz
    Material Management Quiz
    Sales & Distribution Quiz
    Human Resource Quiz
    Netweaver Quiz
    Customer Relationship Management Quiz
    Production and Planning Quiz
    Networking Programming Quizzes
    Corba Quiz
    Networking Quiz
    Microsoft Office Quizzes
    Microsoft Word Quiz
    Microsoft Outlook Quiz
    Microsoft PowerPoint Quiz
    Microsoft Publisher Quiz
    Microsoft Excel Quiz
    Microsoft Front Page Quiz
    Microsoft InfoPath Quiz
    Microsoft Access Quiz
    Accounting Quizzes
    Financial Accounting Quiz
    Managerial Accounting Quiz
    Testimonials | Contact Us | Link to Us | Site Map
    Copyright © 2008. Academic Tutorials.com. All rights reserved Privacy Policies | About Us
    Our Portals : Academic Tutorials | Best eBooksworld | Beyond Stats | City Details | Interview Questions | Discussions World | Excellent Mobiles | Free Bangalore | Give Me The Code | Gog Logo | Indian Free Ads | Jobs Assist | New Interview Questions | One Stop FAQs | One Stop GATE | One Stop GRE | One Stop IAS | One Stop MBA | One Stop SAP | One Stop Testing | Webhosting in India | Dedicated Server in India | Sirf Dosti | Source Codes World | Tasty Food | Tech Archive | Testing Interview Questions | Tests World | The Galz | Top Masala | Vyom | Vyom eBooks | Vyom International | Vyom Links | Vyoms | Vyom World
    Copyright © 2003-2017 Vyom Technosoft Pvt. Ltd., All Rights Reserved.