Manual Chapter : Implementing Proxy SSL on a Single BIG-IP System

Applies To:

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BIG-IP LTM

  • 11.6.5, 11.6.4, 11.6.3, 11.6.2, 11.6.1
Manual Chapter

Implementing Proxy SSL on a Single BIG-IP System

Overview: Direct client-server authentication with application optimization

When setting up the BIG-IP® system to process application data, you might want the destination server to authenticate the client system directly, for security reasons, instead of relying on the BIG-IP system to perform this function. Retaining direct client-server authentication provides full transparency between the client and server systems, and grants the server final authority to allow or deny client access.

The feature that makes it possible for this direct client-server authentication is known as Proxy SSL. You enable this feature when you configure the Client SSL and Server SSL profiles.

Note: To use this feature, you must configure both a Client SSL and a Server SSL profile.

Without the Proxy SSL feature enabled, the BIG-IP system establishes separate client-side and server-side SSL connections and then manages the initial authentication of both the client and server systems.

With the Proxy SSL feature, the BIG-IP system makes it possible for direct client-server authentication by establishing a secure SSL tunnel between the client and server systems and then forwarding the SSL handshake messages from the client to the server and vice versa. After the client and server successfully authenticate each other, the BIG-IP system uses the tunnel to decrypt the application data and intelligently manipulate (optimize) the data as needed.

Task summary

To implement direct client-to-server SSL authentication, as well as application data manipulation, you perform a few basic configuration tasks. Note that you must create both a Client SSL and a Server SSL profile, and enable the Proxy SSL feature in both profiles.

Before you begin, verify that the client system, server system, and BIG-IP® system contain the appropriate SSL certificates for mutual authentication.

Important: The BIG-IP certificate and key referenced in a Server SSL profile must match those of the server system.

As you configure your network for Proxy SSL, keep in mind the following considerations:

  • Proxy SSL supports only the RSA key exchange. For proper functioning, the client and server must not negotiate key exchanges or cipher suites that Proxy SSL does not support, such as the Diffie-Hellman (DH) and Ephemeral Diffie-Hellman (DHE) key exchanges, and the Elliptic Curve Cryptography (ECC) cipher suite. To avoid this issue, you can either configure the client so that the ClientHello packet does not include DH, DHE, or ECC; or configure the server to not accept DH, DHE, or ECC.
  • Proxy SSL supports only the NULL compression method.

Task list

Creating a custom Server SSL profile

You perform this task to create a Server SSL profile that makes it possible for direct client-server authentication while still allowing the BIG-IP® system to perform data optimization, such as decryption and encryption. This profile applies to server-side SSL traffic only.
Important: The certificate and key that you specify in this profile must match the certificate/key pair that you expect the back-end server to offer. If the back-end server has two or more certificates to offer, you must create a separate Server SSL profile for each certificate and then assign all of the Server SSL profiles to a single virtual server.
  1. On the Main tab, click Local Traffic > Profiles > SSL > Server .
    The SSL Server profile list screen opens.
  2. Click Create.
    The New Server SSL Profile screen opens.
  3. In the Name field, type a unique name for the profile.
  4. Select serverssl in the Parent Profile list.
  5. From the Certificate list, select a relevant certificate name.
  6. From the Key list, select a relevant key name.
  7. For the Proxy SSL setting, select the check box.
  8. From the Configuration list, select Advanced.
  9. Modify all other settings, as required.
  10. Choose one of the following actions:
    • If you need to create another Server SSL profile, click Repeat.
    • If you do not need to create another Server SSL profile, click Finished.
All relevant Server SSL profiles now appear on the SSL Server profile list screen.

Creating a custom Client SSL profile

You perform this task to create a Client SSL profile that makes it possible for direct client-server authentication while still allowing the BIG-IP system to perform data optimization, such as decryption and encryption. This profile applies to client-side SSL traffic only.

  1. On the Main tab, click Local Traffic > Profiles > SSL > Client .
    The Client profile list screen opens.
  2. Click Create.
    The New Client SSL Profile screen opens.
  3. In the Name field, type a unique name for the profile.
  4. Select clientssl in the Parent Profile list.
  5. For the Proxy SSL setting, select the check box.
  6. From the Configuration list, select Advanced.
  7. Modify all other settings, as required.
  8. Click Finished.
The custom Client SSL profile now appears in the Client SSL profile list screen.

Creating a load balancing pool

You can create a load balancing pool (a logical set of devices such as web servers that you group together to receive and process traffic) to efficiently distribute the load on your server resources.
Note: You must create the pool before you create the corresponding virtual server.
  1. On the Main tab, click Local Traffic > Pools .
    The Pool List screen opens.
  2. Click Create.
    The New Pool screen opens.
  3. In the Name field, type a unique name for the pool.
  4. For the Health Monitors setting, in the Available list, select a monitor type, and click << to move the monitor to the Active list.
    Tip: Hold the Shift or Ctrl key to select more than one monitor at a time.
  5. From the Load Balancing Method list, select how the system distributes traffic to members of this pool.
    The default is Round Robin.
  6. For the Priority Group Activation setting, specify how to handle priority groups:
    • Select Disabled to disable priority groups. This is the default option.
    • Select Less than, and in the Available Members field type the minimum number of members that must remain available in each priority group in order for traffic to remain confined to that group.
  7. Using the New Members setting, add each resource that you want to include in the pool:
    1. In the Node Name field, type a name for the node portion of the pool member.
      This step is optional.
    2. In the Address field, type an IP address.
    3. In the Service Port field, type a port number, or select a service name from the list.
    4. In the Priority field, type a priority number.
      This step is optional.
    5. Click Add.
  8. Click Finished.
The load balancing pool appears in the Pools list.

Creating a virtual server for client-side and server-side SSL traffic

You can specify a virtual server to be either a host virtual server or a network virtual server to manage application traffic.
  1. On the Main tab, click Local Traffic > Virtual Servers .
    The Virtual Server List screen opens.
  2. Click the Create button.
    The New Virtual Server screen opens.
  3. In the Name field, type a unique name for the virtual server.
  4. In the Destination Address field, type an address, as appropriate for your network.
    The supported format is address/prefix, where the prefix length is in bits. For example, an IPv4 address/prefix is 10.0.0.1 or 10.0.0.0/24, and an IPv6 address/prefix is ffe1::0020/64 or 2001:ed8:77b5:2:10:10:100:42/64. When you use an IPv4 address without specifying a prefix, the BIG-IP® system automatically uses a /32 prefix.
  5. In the Service Port field, type a port number or select a service name from the Service Port list.
  6. For the SSL Profile (Client) setting, from the Available list, select the name of the custom Client SSL proxy profile you previously created, and using the Move button, move the name to the Selected list.
    Important: To enable proxy SSL functionality, you can either:
    • Disassociate existing Client SSL and Server SSL profiles from a virtual server and configure the Proxy SSL settings.
    • Create new Client SSL and Server SSL profiles and configure the Proxy SSL settings.
    Then with either option, select the Client SSL and Server SSL profiles on a virtual server. You cannot modify existing Client SSL and Server SSL profiles while they are selected on a virtual server to enable proxy SSL functionality.
  7. For the SSL Profile (Server) setting, from the Available list, select the name of the custom Server SSL proxy profile you previously created, and using the Move button, move the name to the Selected list.
    Important: To enable SSL proxy functionality, you can either:
    • Disassociate existing Client SSL and Server SSL profiles from a virtual server and configure the Proxy SSL settings.
    • Create new Client SSL and Server SSL profiles and configure the Proxy SSL settings.
    Then with either option, select the Client SSL and Server SSL profiles on a virtual server. You cannot modify existing Client SSL and Server SSL profiles while they are selected on a virtual server to enable SSL proxy functionality.
  8. Assign other profiles to the virtual server if applicable.
  9. In the Resources area, from the Default Pool list, select the name of the pool that you created previously.
  10. Click Finished.
The virtual server now appears in the Virtual Server List screen.

Implementation result

After you complete the tasks in this implementation, the BIG-IP® system ensures that the client system and server system can initially authenticate each other directly. After client-server authentication, the BIG-IP system can intelligently decrypt and manipulate the application data according to the configuration settings in the profiles assigned to the virtual server.