Manual Chapter : Managing Client-Side HTTP Traffic Using a CA-Signed RSA Certificate

Applies To:

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BIG-IP AAM

  • 13.0.1, 13.0.0

BIG-IP APM

  • 13.0.1, 13.0.0

BIG-IP Link Controller

  • 13.0.1, 13.0.0

BIG-IP Analytics

  • 13.0.1, 13.0.0

BIG-IP LTM

  • 13.0.1, 13.0.0

BIG-IP AFM

  • 13.0.1, 13.0.0

BIG-IP PEM

  • 13.0.1, 13.0.0

BIG-IP DNS

  • 13.0.1, 13.0.0

BIG-IP ASM

  • 13.0.1, 13.0.0
Manual Chapter

Overview: Managing client-side HTTP traffic using a CA-signed RSA certificate

When you want to manage HTTP traffic over SSL, you can configure the BIG-IP® system to perform the SSL handshake that target web servers normally perform.

A common way to configure the BIG-IP system is to enable client-side SSL, which makes it possible for the system to decrypt client requests before sending them on to a server, and encrypt server responses before sending them back to the client. In this case, you need to install only one SSL key/certificate pair on the BIG-IP system.

This implementation uses a certificate signed by an RSA certificate authority (CA) to authenticate HTTP traffic.

Task summary

To implement client-side authentication using HTTP and SSL with a certificate signed by a certificate authority, you perform a few basic configuration tasks.

Task list

Requesting an RSA certificate from a certificate authority

You can generate a request for an RSA digital certificate and then copy or submit it to a trusted certificate authority for signature.
  1. On the Main tab, click System > Certificate Management > Traffic Certificate Management .
    The Traffic Certificate Management screen opens.
  2. Click Create.
  3. In the Name field, type a unique name for the SSL certificate.
  4. From the Issuer list, select Certificate Authority.
  5. In the Common Name field, type a name.
    This is typically the name of a web site, such as www.siterequest.com.
  6. In the Division field, type your department name.
  7. In the Organization field, type your company name.
  8. In the Locality field, type your city name.
  9. In the or State or Province field, type your state or province name.
  10. From the Country list, select the name of your country.
  11. In the E-mail Address field, type your email address.
  12. In the Lifetime field, type a number of days, or retain the default, 365.
  13. In the Subject Alternative Name field, type a name.
    This name is embedded in the certificate for X509 extension purposes.
    By assigning this name, you can protect multiple host names with a single SSL certificate.
  14. In the Challenge Password field, type a password.
  15. In the Confirm Password field, re-type the password you typed in the Challenge Password field.
  16. From the Key Type list, select RSA.
  17. From the Size list, select a key size, in bits.
  18. Click Finished.
    The Certificate Signing Request screen displays.
  19. Do one of the following to download the request into a file on your system.
    • In the Request Text field, copy the certificate.
    • For Request File, click the button.
  20. Follow the instructions on the relevant certificate authority web site for either pasting the copied request or attaching the generated request file.
  21. Click Finished.
    The Certificate Signing Request screen displays.
The generated RSA certificate request is submitted to a trusted certificate authority for signature.

Creating a custom HTTP profile

An HTTP profile defines the way that you want the BIG-IP®system to manage HTTP traffic.
Note: Other HTTP profile types (HTTP Compression and Web Acceleration) enable you to configure compression and cache settings, as required. Use of these profile types is optional.
  1. On the Main tab, click Local Traffic > Profiles > Services > HTTP .
    The HTTP profile list screen opens.
  2. Click Create.
    The New HTTP Profile screen opens.
  3. In the Name field, type a unique name for the profile.
  4. From the Parent Profile list, select http.
  5. Select the Custom check box.
  6. Modify the settings, as required.
  7. Click Finished.
The custom HTTP profile now appears in the HTTP profile list screen.

Creating a custom Client SSL profile

After you have built the cipher string that you want the BIG-IP to use to negotiate client-side SSL connections, you create a custom Client SSL profile. You create the profile when you want the BIG-IP® system to terminate client-side SSL traffic for the purpose of decrypting client-side ingress traffic and encrypting client-side egress traffic. By terminating client-side SSL traffic, the BIG-IP system offloads these decryption/encryption functions from the destination server. When you perform this task, you can specify multiple certificate key chains, one for each key type (RSA, DSA, and ECDSA). This allows the BIG-IP system to negotiate secure client connections using different cipher suites based on the client's preference.
Note: At a minimum, you must specify a certificate key chain that includes an RSA key pair. Specifying certificate key chains for DSA and ECDSA key pairs is optional, although highly recommended.
  1. On the Main tab, click Local Traffic > Profiles > SSL > Client .
    The Client SSL 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. From the Parent Profile list, select clientssl.
  5. Select the Custom check box.
    The settings become available for change.
  6. For the Certificate Key Chain setting, click Add.
    1. From the Certificate list, select a certificate name.
      This is the name of a certificate that you installed on the BIG-IP® system. If you have not generated a certificate request nor installed a certificate on the BIG-IP system, and the BIG-IP system is not part of a device service clustering (DSC) configuration, you can specify the name of the existing certificate named default.
      Important: If the BIG-IP system is part of a DSC Sync-Failover group, always select a non-default certificate name, and ensure that this same certificate name is specified in every instance of this SSL profile in the device group. Taking these actions helps to ensure that SSL handshakes are successful after a failover event.
    2. From the Key list, select the name of the key associated with the certificate specified in the previous step.
      This is the name of a key that you installed on the BIG-IP® system. If you have not installed a key on the BIG-IP system, and the BIG-IP system is not part of a device service clustering (DSC) configuration, you can specify the name of the existing key named default.
      Important: If the BIG-IP system is part of a DSC Sync-Failover group, always select a non-default key name, and ensure that this same key name is specified in every instance of this SSL profile in the device group. Taking these actions helps to ensure that SSL handshakes are successful after a failover event.
    3. From the Chain list, select the chain that you want to include in the certificate key chain.
      A certificate chain can contain either a series of public key certificates in Privacy Enhanced Mail (PEM) format or a series of one or more PEM files. A certificate chain can contain certificates for Intermediate certificate Authorities (CAs).
      Note: The default self-signed certificate and the default CA bundle certificate are not appropriate for use as a certificate chain.
    4. For the Passphrase field, type a string that enables access to SSL certificate/key pairs that are stored on the BIG-IP system with password protection.
      This setting is optional. For added security, the BIG-IP system automatically encrypts the pass phrase itself. This pass phrase encryption process is invisible to BIG-IP® system administrative users.
    5. Click Add.
  7. Click Add and repeat the process for all certificate key chains that you want to specify. At a minimum, you must specify an RSA certificate key chain.
    Sample configuration with three key types specified

    Sample configuration with three key types specified

    The result is that all specified key chains appear in the text box.
  8. For the OCSP Stapling setting, select the check box.
    This setting is optional. To enable OCSP stapling, you must first create an OCSP Stapling profile.
  9. For the Notify Certificate Status to Virtual Server setting, select the check box.
    This setting is optional.
  10. For the Ciphers setting, specify a cipher group or cipher string by choosing one of these options.
    Note: If you specified an ECDSA certificate key chain in the Certificate Key Chain setting, you must include the cipher string ECDHE_ECDSA in the cipher group or cipher string that you specify in the Ciphers setting. (At a minimum, you should specify a cipher group or string such as DEFAULT:ECDHE_ECDSA.) This is necessary to ensure successful cipher negotiation when the BIG-IP system is offered an ECDSA-based certificate only.
    Option Description
    Cipher Group

    Select an existing cipher group from the list when you want to use a system-defined or custom cipher group to define the ciphers that the BIG-IP system uses for negotiating SSL connections. Here's an example of the Ciphers setting where we've selected a custom cipher group that we created earlier.

    Cipher String

    Type a cipher string in the box if you want to manually specify a cipher string instead of selecting a cipher group. For security and performance reasons, consider following these recommendations:

    • Always append ciphers to the DEFAULT cipher string.
    • Type a cipher string that includes the ECC key type, because its shorter length speeds up encryption and decryption while still offering virtually the same level of security.
    • Disable ADH ciphers but also include the keyword HIGH. To do this, just include both !ADH and :HIGH in your cipher string.
    • For AES, DES, and RC4 encryption types, make sure you specify the DHE key exchange method. DHE uses Forward Privacy, which creates a key that it throws away after each session so that the same session key never gets used twice. When you use DHE, make sure that the SSL private key isn't being shared with a monitoring system or a security device like an intrusion detection or prevention system. Also, diagnostic tools like ssldump won't work when you're using Forward Secrecy.
    • Disable EXPORT ciphers by including !EXPORT in the cipher string.
    • If you can live with removing support for the SSLv3 protocol version, do it. This protocol version is not secure. Simply include :!SSLv3 in any cipher string you type.

    Here's an example of the Ciphers setting where we have opted to manually type the cipher string DEFAULT:ECDHE-RSA-AES-128-GCM-SHA256:!ADH:!EXPORT:HIGH:

  11. Configure all other profile settings as needed.
  12. Click Finished.
After performing this task, you can see the custom Client SSL profile in the list of Client SSL profiles on the system.
You must also assign the profile to a virtual server.

Creating a pool to process HTTP traffic

You can create a pool of web servers to process HTTP requests.
  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, from the Available list, select the http monitor and move the monitor to the Active list.
  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. Type an IP address in the Address field.
    2. Type 80 in the Service Port field, or select HTTP from the list.
    3. (Optional) Type a priority number in the Priority field.
    4. Click Add.
  8. Click Finished.
The new pool appears in the Pools list.

Creating a virtual server for client-side HTTP traffic

You can specify a virtual server to be either a host virtual server or a network virtual server to manage HTTP traffic over SSL.
  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 the IP address in CIDR format.
    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.
    Note: The IP address you type must be available and not in the loopback network.
  5. In the Service Port field, type 443, or select HTTPS from the list.
  6. From the HTTP Profile list, select the HTTP profile that you previously created.
  7. For the SSL Profile (Client) setting, from the Available list, select the name of the Client SSL profile you previously created and move the name to the Selected list.
  8. In the Resources area, from the Default Pool list, select the name of the pool that you created previously.
  9. Click Finished.
After performing this task, the virtual server appears in the Virtual Server List screen.

Implementation results

After you complete the tasks in this implementation, the BIG-IP® system can authenticate and decrypt HTTP traffic coming from a client system, using an RSA digital certificate. The BIG-IP system can also re-encrypt server responses before sending them back to the client.