IPsec - Internet Protocol Security
====================================

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      **What is IPsec?**

        IPsec (Internet Protocol Security) is a suite of protocols that secures IP communications by encrypting and authenticating each IP packet.
        When used outside of VPN, IPsec operates directly between endpoints (e.g., host-to-host or network-to-network) without creating a virtual tunnel.
        Think of it as a secure envelope for each individual IP packet, without the need for a full VPN tunnel.

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      **Why is IPsec important outside VPN?**

        * Data Confidentiality: Encrypts individual IP packets to prevent unauthorized access.
        * Data Integrity: Ensures packets haven’t been altered during transit.
        * Authentication: Verifies the identity of communicating devices.
        * Granular Security: Secures specific traffic flows without tunneling all traffic.
        * Low Overhead: No need for virtual interfaces or VPN clients.

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      **How IPsec works (in simple steps):**

        * Negotiation: Devices agree on security parameters using IKE (Internet Key Exchange).
        * Authentication: Devices authenticate using pre-shared keys or certificates.
        * Encryption & Integrity: Each IP packet is encrypted and signed.
        * Transmission: Secure packets are sent directly between endpoints.
        * Decryption: Receiving device decrypts and verifies each packet.

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      **Where is IPsec used?**

        * Host-to-Host Security: Direct secure communication between two servers or endpoints.
        * Intranet Protection: Secures internal traffic within a corporate LAN or WAN.
        * IoT Security: Protects data exchanged between IoT devices and control systems.
        * Mobile IP: Maintains secure sessions as users move across networks.
        * VoIP & Video: Secures real-time communication without tunneling overhead.

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      **Why OSI Layer: Network Layer (Layer 3)?**

        * IPsec operates directly on IP packets, securing all traffic regardless of application.
        * It works below the transport layer (TCP/UDP) and above the data link layer, making it part of the Network Layer.
        * This allows IPsec to secure all communication without modifying higher-layer protocols.

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        Topics in this section,

                * :ref:`Learnings in this section <IPsec_step1>`

                * :ref:`Terminology <IPsec_step2>`

                * :ref:`Version Info <IPsec_step3>`

                * :ref:`IPsec Version&RFC Details <IPsec_step5>`

                * :ref:`IPsec Basic Setup on Ubuntu using IPv4 <IPsec_step20>`

                * :ref:`IPsec Basic Setup on Ubuntu using IPv6 <IPsec_step21>`

                * :ref:`IPsec Protocol Packet Details <IPsec_step6>`

                * :ref:`IPsec Usecases <IPsec_step7>`

                * :ref:`IPsec Basic Features <IPsec_step8>`
                    
                * :ref:`IPsec Feature : Encryption <IPsec_step9>` 

                * :ref:`IPsec Feature : Authentication <IPsec_step10>`

                * :ref:`IPsec Feature : Integrity Checking <IPsec_step11>`  

                * :ref:`IPsec Feature : Transport Mode Support <IPsec_step12>`  

                * :ref:`IPsec Feature : Key Exchange (IKE/IKEv2) <IPsec_step13>`

                * :ref:`IPsec Feature : Security Associations (SAs) <IPsec_step14>`

                * :ref:`IPsec Feature : Protocol Support (ESP & AH) <IPsec_step15>`   

                * :ref:`IPsec Feature : NAT Traversal <IPsec_step16>` 

                * :ref:`IPsec Feature : Replay Protection <IPsec_step17>` 

                * :ref:`IPsec Feature : Flexible Algorithm Support <IPsec_step18>` 

                * :ref:`Reference links <IPsec_step19>`


.. _IPsec_step1:

.. tab-set::

    .. tab-item:: Learnings in this section

        * In this section, you are going to learn

.. _IPsec_step2:

.. tab-set::

    .. tab-item:: Terminology
        
       * Terminology


.. _IPsec_step3:

.. tab-set::

    .. tab-item:: Version Info
    
         * Version Info


.. _IPsec_step5:

.. tab-set::

    .. tab-item:: IPsec Version&RFC Details

        
         .. csv-table:: 
               :file: ./IPsec/IPssec_Version_&_RFC_Details.csv
               :widths: 10,10,10,30
               :header-rows: 1

.. _IPsec_step20:

.. tab-set::

    .. tab-item:: IPsec Basic Setup on Ubuntu using IPv4

      **Setup**



.. _IPsec_step21:

.. tab-set::

   .. tab-item:: IPsec Basic Setup on Ubuntu using IPv6
       
    **Setup**



.. _IPsec_step6:

.. tab-set::

    .. tab-item:: IPsec Protocol Packet Details
       
         **Transport Mode with AH**

         .. csv-table:: 
                :file: ./IPsec/IPsec_packetdetails1.csv
                :widths: 10,20,30,10
                :header-rows: 1

         **Transport Mode with ESP**

         .. csv-table::
                :file: ./IPsec/IPsec_packetdetails2.csv
                :widths: 10,20,30,10
                :header-rows: 1
        

.. _IPsec_step7:

.. tab-set::

    .. tab-item:: IPsec Usecases
        
        
         .. csv-table:: 
               :file: ./IPsec/IPsec_Use_Cases.csv
               :widths: 10,20,30
               :header-rows: 1

.. _IPsec_step8:

.. tab-set::

    .. tab-item:: IPsec Basic Features
    
         
         .. csv-table:: 
                  :file: ./IPsec/IPsec_Basic_Features.csv
                  :widths: 10,10,30
                  :header-rows: 1

.. _IPsec_step9:

.. tab-set::

    .. tab-item:: IPsec Feature : Encryption

          **Encryption - Testcases**

          .. csv-table:: 
                 :file: ./IPsec/IPsec_Feature1_Encryption_TestCases.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


   
.. _IPsec_step10:

.. tab-set::

    .. tab-item:: IPsec Feature : Authentication

         **Authentication - Testcases**

         .. csv-table:: 
                :file: ./IPsec/IPsec_Feature2_Authentication_TestCases.csv
                :widths: 10,10,30,20
                :header-rows: 1


.. _IPsec_step11:

.. tab-set::

    .. tab-item:: IPsec Feature : Integrity Checking

        **Integrity Checking - Testcases**

        .. csv-table:: 
                 :file: ./IPsec/IPsec_Feature3_Integrity_Checking_TestCases.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _IPsec_step12:

.. tab-set::

    .. tab-item:: IPsec Feature : Transport Mode Support

          **Transport Mode Support - Testcases**

          .. csv-table:: 
                :file: ./IPsec/IPsec_Feature4_Transport_Mode_Support_TestCases.csv
                :widths: 10,10,30,20
                :header-rows: 1



.. _IPsec_step13:

.. tab-set::

    .. tab-item:: IPsec Feature : Key Exchange (IKE/IKEv2)

         **Key Exchange (IKE/IKEv2) - Testcases**

         .. csv-table:: 
                 :file: ./IPsec/IPsec_Feature5_Key_Exchange(IKE_IKEv2)_TestCases.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


 
.. _IPsec_step14:

.. tab-set::

    .. tab-item:: IPsec Feature : Security Associations (SAs)

         **Security Associations (SAs) - Testcases**

         .. csv-table:: 
                  :file: ./IPsec/IPsec_feature6_Security_Associations(SAs)_TestCases.csv
                  :widths: 10,10,30,20
                  :header-rows: 1


.. _IPsec_step15:

.. tab-set::

    .. tab-item:: IPsec Feature : Protocol Support (ESP & AH)
   
          **Protocol Support (ESP & AH) - Testcases**

          .. csv-table:: 
                 :file: ./IPsec/IPsec_Feature7_Protocol_Support(ESP&AH)_TestCases.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _IPsec_step16:

.. tab-set::

    .. tab-item:: IPsec Feature : NAT Traversal

         **NAT Traversal - Testcases**

         .. csv-table:: 
                 :file: ./IPsec/IPsec_Feature8_NAT_Traversal_TestCases.csv
                 :widths: 10,10,30,20
                 :header-rows: 1


.. _IPsec_step17:

.. tab-set::

    .. tab-item:: IPsec Feature : Replay Protection

        **Replay Protection - Testcases**

        .. csv-table::
                :file: ./IPsec/IPsec_Feature9_Replay_Protection_Test Cases.csv
                :widths: 10,10,30,20
                :header-rows: 1


.. _IPsec_step18:

.. tab-set::

    .. tab-item:: IPsec Feature : Flexible Algorithm Support

        **Flexible Algorithm Support - Testcases**

        .. csv-table::
                :file: ./IPsec/IPsec_Feature10_Flexible_Algorithm_Support_TestCases.csv
                :widths: 10,10,30,20
                :header-rows: 1


.. _IPsec_step19:

.. tab-set::

    .. tab-item:: Reference links
     
       * Reference links