Configuring Radware Alteon SSL Offloading With Perfect Forward Secrecy

Radware Alteon can terminate client TLS connections at the application delivery controller, inspect and balance the resulting HTTP traffic, and establish a separate connection to backend servers. This reduces cryptographic overhead on web servers while providing a central place to enforce TLS versions, cipher suites, HTTP security headers, and certificate rotation.

Perfect Forward Secrecy (PFS) changes the security properties of that design. With ephemeral Diffie-Hellman exchanges, usually ECDHE, the compromise of a server’s long-term private key does not expose previously captured sessions. The configuration must cover the client-facing virtual service, certificate chain, cipher policy, and any re-encryption towards the application tier.

Design	Client Connection	Alteon-to-Server Connection	PFS Consideration
TLS offload	HTTPS	HTTP	PFS applies to the client side only
TLS bridging	HTTPS	HTTPS	PFS policies are required on both sides
TLS passthrough	HTTPS	HTTPS	Backend owns TLS; Alteon has limited visibility
Re-encryption with inspection	HTTPS	HTTPS	Strongest separation, with greater CPU and certificate administration

Choose The Termination Boundary

Start by deciding where encryption ends. For ordinary public web applications, Alteon commonly accepts HTTPS on the virtual IP, decrypts the request, and forwards HTTP to a protected server VLAN. This is straightforward, but traffic between the ADC and application servers is visible on that network.

TLS bridging is preferable where internal traffic must remain encrypted, such as payment systems, privileged administration portals, or workloads subject to strict data-handling controls. The backend pool then needs its own certificate trust configuration, and Alteon must validate the application server certificate when that feature is enabled.

Australian organisations often place public services in AWS Sydney (ap-southeast-2) or Melbourne (`ap-southeast-4), while retaining application servers in a local data centre. In that hybrid pattern, confirm that the chosen termination point does not create unnecessary cross-city latency or move regulated data outside the approved jurisdiction.

Prepare Certificates And Cipher Policy

Import the server certificate, private key, and complete intermediate chain into Alteon before editing the virtual service. Use a clear naming convention that identifies the hostname and expiry month. Keeping the intermediate chain complete prevents browser warnings and avoids inconsistent behaviour between Chrome, Safari, mobile clients, and API libraries.

For PFS, prioritise ECDHE suites with AES-GCM or ChaCha20-Poly1305. A typical TLS 1.2 policy gives preference to ECDHE-ECDSA-AES256-GCM-SHA384, ECDHE-RSA-AES256-GCM-SHA384, and their AES-128 equivalents. TLS 1.3 cipher selection is handled differently, so confirm what the installed Alteon software release supports rather than copying a TLS 1.2 list into a TLS 1.3 policy.

Disable SSLv3, TLS 1.0, and TLS 1.1 unless an identified legacy dependency requires them. If older clients remain in the Australian market, isolate them behind a separate hostname or listener instead of weakening the primary policy. Align the result with the organisation’s Essential Eight controls and internal certificate management process.

Build The Alteon Virtual Service

Create or select the virtual server bound to the public address, then add an HTTPS virtual service on port 443. Attach the certificate profile and the PFS cipher policy to that service. The service should forward to a pool containing the application servers, with a health check that tests a meaningful endpoint rather than merely confirming that TCP port 80 is open.

For HTTP backends, configure the service to send the correct Host header and preserve the original client address through X-Forwarded-For or the platform’s equivalent. Set X-Forwarded-Proto: https so applications generate secure redirects and mark cookies correctly. Review Alteon’s source NAT behaviour as well: retaining the client IP may help auditing, while SNAT can simplify return routing.

A practical change window in Sydney or Melbourne should include DNS TTL review, certificate validation, and a rollback path. Teams supporting Brisbane, Perth, or remote branch users should test from more than the primary office because carrier routing and regional latency can expose problems that an internal test does not show.

Preserve Application And Audit Context

TLS offload changes what the backend sees. Unless headers are inserted consistently, an application may believe a request arrived over HTTP, issue redirect loops, or create cookies without the Secure attribute. Framework settings must explicitly trust the proxy headers only from the Alteon management or server-side network.

Logging should capture the virtual service, selected pool member, TLS version, negotiated cipher, response status, and request correlation identifier. Avoid logging credentials, session cookies, or sensitive payloads. If the environment uses central monitoring, send Alteon events to the existing syslog or SIEM platform and retain certificate-expiry alerts separately from traffic alerts.

Operational teams can apply the same disciplined remediation approach used for other infrastructure platforms. For example, VMware health alerts demonstrate the value of recording symptoms, scope, corrective action, and verification rather than simply clearing an alarm.

Validate PFS Without Guesswork

Test the public hostname from an external network and inspect the negotiated protocol and cipher. OpenSSL, browser developer tools, and dedicated TLS scanners can confirm whether an ECDHE exchange is selected. A certificate using RSA does not prevent PFS; the key exchange is what matters, so an ECDHE-RSA result can still provide forward secrecy.

Check the full request path: HTTP-to-HTTPS redirects, host-based routing, authentication callbacks, WebSockets, large uploads, and session persistence. Confirm that the backend receives the expected Host, X-Forwarded-For, and X-Forwarded-Proto values. A small TCP diagnostic tool such as this Python port forwarder can assist with controlled connectivity tests, though it should not replace proper TLS inspection.

Useful validation evidence includes:

• The negotiated protocol and cipher from an external test
• A complete certificate chain with the expected subject alternative names
• Successful application health checks and normal pool failover
• Backend logs showing the original host and secure transport indicator

Operate The Design In Production

Certificate renewal is the most common source of avoidable outages. Import the replacement certificate ahead of expiry, bind it to the correct SSL profile, and test it on a staging VIP where possible. Schedule an explicit Alteon configuration save after validation, then retain a dated backup of the previous configuration for rollback.

Monitor handshake failures, TLS alerts, pool member status, CPU utilisation, memory pressure, and connection rates. PFS increases the value of ephemeral key exchanges, while TLS inspection and re-encryption can increase ADC resource consumption. Establish thresholds before a major launch, especially for retail workloads that may spike during Boxing Day sales or end-of-financial-year activity.

A concise production runbook should contain:

• Certificate names, expiry dates, and approved cipher policy
• Virtual service, pool, health-check, and SNAT dependencies
• Test commands and expected HTTP response behaviour
• Rollback steps and the responsible on-call contacts

After a software upgrade or cipher-policy change, repeat the external TLS test and review application logs from both sides of the ADC. This confirms that forward secrecy remains active while routing, observability, and backend trust continue to operate as designed.