Generating a CSR and Installing an SSL Certificate on F5 BIG-IP
Lisa AndersonShare
F5 BIG-IP terminates Transport Layer Security (TLS) for some of the busiest applications on the internet, and its SSL Certificate model has one extra layer that web servers lack. The SSL Certificate never attaches to traffic directly. It lives inside a Client SSL profile, and the profile attaches to a virtual server.
Once that mental model clicks, the whole process becomes predictable.
This guide applies to BIG-IP version 13 and later through the Configuration Utility.
Generating the Certificate Signing Request
Navigate to System, then Certificate Management, then Traffic Certificate Management, and open the SSL Certificate List. Click Create, give the object a recognizable name, and set the Issuer to Certificate Authority, which produces a Certificate Signing Request (CSR) rather than a self-signed entry.
Set the Common Name to the exact hostname being secured, complete the organization fields, and choose RSA at 2048 bits or stronger. Additional hostnames belong in the Subject Alternative Name field. When you finish, BIG-IP displays the request text for copying, and the Private Key remains safely on the device.
Submit the request when placing your order and complete validation as normal. Learn About the Validation Procedure 🔗
Importing the Issued SSL Certificate and Chain
Download the issued SSL Certificate and the ca-bundle of Intermediate Certificates from the Certificate Authority (CA) once issuance completes. Both stay available in the tracking system. View Our Tracking & SSL Management 🔗
In the SSL Certificate List, open the object created earlier and import the issued file against it, which pairs the SSL Certificate with its waiting Private Key. Importing it as a brand new object instead leaves the key orphaned, so always work through the original entry.
Import the ca-bundle separately through Import, choosing Certificate as the type and giving it a clear name such as yourdomain-chain. BIG-IP treats the chain as its own object that profiles reference independently. Learn About Intermediate Certificates 🔗
Building the Client SSL Profile
Navigate to Local Traffic, then Profiles, then SSL, and open Client. Create a new profile with clientssl as the parent, then tick the custom box beside Certificate Key Chain and add an entry.
Select your SSL Certificate, its key, and the chain object imported above, then save the profile. The chain selection here is what delivers the Intermediate Certificates to connecting clients, and leaving it at None is the most common cause of mobile device warnings on this platform.
Attaching the Profile to a Virtual Server
Open Local Traffic, then Virtual Servers, and edit the virtual server listening on port 443. In the SSL Profile (Client) section, move your new profile into the selected column and update.
The change takes effect immediately, with existing connections finishing on the old configuration while new connections receive the new SSL Certificate.
Tip : When the time comes to replace the SSL Certificate, import the replacement against the same objects rather than building a new profile. Every virtual server referencing the profile picks the replacement up at once, which turns a multi-application change into a single step.
With the profile attached, the final step is confirming what clients receive.
Verifying the Installation
Connect to the application hostname and confirm the SSL Certificate details in the browser. Then run an external scan, which confirms the chain object is actually selected in the profile and reaching fresh clients. Trustico® provides free checking tools for this confirmation. Explore Our Trustico® SSL Tools 🔗
BIG-IP commonly terminates TLS and forwards plain traffic to the backend pool, an architecture with measurable performance benefits worth understanding when planning where SSL Certificates live. Learn About SSL Offloading 🔗
Troubleshooting Common Installation Problems
A key and SSL Certificate mismatch error during import means the file was issued from a different request than the object holds, typically because the object was recreated after submission. A reissue against the current request resolves it. Learn About Reissuing Your SSL Certificate 🔗
Chain warnings on mobile devices mean the Chain field in the Client SSL profile is set to None. Select the imported chain object and save.
If the virtual server still serves the previous SSL Certificate, confirm the correct profile sits in the selected column and that no other Client SSL profile overrides it for the same traffic.
Professional Installation Assistance
BIG-IP deployments frequently carry dozens of applications, and untangling which profile serves which virtual server takes platform familiarity.
Trustico® offers a Premium Installation service where our technicians complete the installation on your behalf. Discover Our Premium Installation Service 🔗
