Configuring Radware DefensePro for SSL/TLS Inspection and Decryption

Encrypted traffic protects applications and users, but it also hides volumetric, protocol, and application-layer attacks from network security controls. Radware DefensePro can help expose threats within TLS sessions when it is deployed with the required inspection capabilities, certificates, licenses, and traffic flow design.

The implementation is more involved than enabling a checkbox. TLS decryption affects certificates, private-key security, session capacity, latency, bypass behavior, and application compatibility. A sound configuration begins by identifying which traffic must be inspected and where DefensePro sits in the packet path.

Exact menu names and supported ciphers vary between DefensePro releases, hardware platforms, virtual editions, and related Radware products. Use the version-specific documentation for final syntax, and validate the design in a maintenance window before applying it to production traffic.

Confirm the Inspection Architecture

Start by documenting the path from client to application. In a reverse-proxy design, DefensePro may receive traffic before an Alteon load balancer or web server. In another design, a dedicated TLS visibility device decrypts traffic and forwards cleartext or re-encrypted sessions toward DefensePro. The correct configuration depends on whether DefensePro performs the TLS proxy function directly or protects traffic after decryption.

Define the protected VIPs, backend servers, listening ports, routing interfaces, and expected traffic volume. Record whether traffic uses TLS passthrough, TLS termination at a load balancer, mutual TLS, HTTP/2, HTTP/3, or WebSocket upgrades. These details determine whether inspection is technically possible and where policy enforcement belongs.

Confirm that the DefensePro software release supports the desired SSL/TLS inspection mode. Check licensing, inspection throughput, concurrent session capacity, supported protocol versions, and hardware acceleration. A device sized for packet-based DDoS mitigation may require additional capacity for certificate processing and stateful TLS sessions.

Prepare Certificates and Private Keys

TLS interception requires a certificate strategy. For inbound traffic to applications, the inspection component generally needs the server certificate and its corresponding private key, or it must receive traffic after another device has already terminated TLS. For outbound inspection, clients must trust a local certificate authority that signs substitute certificates generated by the inspection service.

Import only the certificates required for the selected virtual services. Confirm the certificate chain, subject alternative names, key type, expiration date, and private-key format before enabling the policy. A missing intermediate certificate can create failures that appear to be application or browser problems.

Protect private keys as production secrets. Use encrypted management access, role-based administration, secure backups, and a controlled rotation process. Do not export keys to troubleshooting workstations or store them in plain-text automation repositories. If the organization uses a hardware security module or centralized certificate manager, include that dependency in the design.

Configure TLS Policies and Bypass Rules

Create an inspection policy that matches the intended VIPs, ports, source networks, and application services. Begin with a narrow scope rather than decrypting every TLS connection. A limited policy makes it easier to compare session counts, CPU utilization, handshake failures, and security events before expansion.

Set explicit handling for unsupported or risky traffic. Common exceptions include financial applications, healthcare systems, certificate-pinned mobile clients, administrative interfaces, mutual-TLS services, and applications with strict privacy requirements. Bypass rules should be based on known destinations and business requirements, not broad exclusions such as an entire protocol or country.

Select the strongest protocol and cipher settings supported by the application estate. Disable obsolete SSL and TLS versions where compatibility allows, while testing TLS 1.2 and TLS 1.3 behavior separately. TLS 1.3 can change visibility and handshake behavior, and some inspection implementations require specific support or a controlled fallback. Avoid weakening global security settings to accommodate a single legacy service.

Validate Traffic Flow and Failover

Before enabling enforcement, test the complete client-to-server path. Verify DNS resolution, routing symmetry, NAT behavior, certificate presentation, hostname validation, and backend reachability. Use browser diagnostics, OpenSSL, curl, and packet captures from authorized test systems to confirm which certificate is presented at each leg.

A useful test sequence includes a normal HTTPS request, an invalid certificate case, a large response, a long-lived connection, and a request that should trigger a DefensePro security policy. Check whether the device logs the session, forwards the expected response, and preserves required headers and connection behavior.

Test high availability as well. Confirm that certificate objects, inspection policies, session synchronization, and bypass settings are consistent between peers. Simulate a device failure and determine whether traffic fails open, fails closed, or is redirected around the inspection path. The correct choice depends on application criticality and the organization’s risk tolerance.

Compare Deployment Choices

The best placement depends on whether the organization needs DefensePro to terminate TLS, inspect already-decrypted traffic, or protect encrypted sessions using metadata and behavioral controls. The following comparison helps frame the decision before configuration begins.

Deployment approach	TLS visibility	Main dependency	Operational consideration
DefensePro-integrated inspection	Full session visibility when supported	Compatible release, license, certificates, and capacity	Simplifies traffic flow but increases appliance processing requirements
Load balancer terminates TLS first	DefensePro can inspect cleartext or service-side traffic	Correct placement and secure internal segmentation	Protects the backend leg, but the client-side encrypted leg must be addressed
Dedicated TLS visibility device	Full decrypted stream can be sent to DefensePro	Decryption platform, taps or inline links, and forwarding design	Provides separation of duties but adds latency and failure points
TLS passthrough with metadata controls	Limited visibility into payload	SNI, IP, flow, and behavioral detection support	Preserves end-to-end encryption but cannot inspect HTTP content
Selective inspection by VIP or URL class	Visibility for prioritized services	Accurate object matching and exception management	Reduces overhead and limits privacy impact

Keep the inspection boundary documented in network diagrams and change records. Security teams should know whether DefensePro sees the original client address, a proxy address, or a translated source. That information affects rate limits, reputation policies, and incident response.

Monitor Performance and Troubleshoot Failures

After activation, monitor TLS handshakes, concurrent sessions, new connections per second, throughput, CPU, memory, certificate errors, and dropped or bypassed sessions. Compare these values with the baseline collected before inspection. A sudden increase in handshake failures or connection latency often indicates a certificate-chain problem, unsupported cipher, asymmetric routing, or resource exhaustion.

When a client cannot connect, determine whether the failure occurs during DNS, TCP setup, the TLS handshake, HTTP negotiation, or backend communication. Check the certificate presented to the client and compare it with the expected hostname. Then inspect the server-side certificate and the DefensePro event logs. This two-leg approach separates client-facing TLS issues from origin-server problems.

For encrypted floods, distinguish legitimate session volume from attack traffic. SSL negotiation consumes more resources than a simple packet flood, so a policy should limit abusive connection rates while preserving access for known clients and critical services. Tune thresholds gradually and use learning or reporting modes where available before moving to blocking.

Maintain the Configuration Safely

Certificate renewal should be treated as a recurring operational process rather than an emergency change. Track expiration dates, test replacement certificates in advance, and confirm that the complete chain is installed on every relevant node. Keep rollback copies of the previous configuration, but protect any private keys according to organizational security policy.

Review bypass rules, cipher settings, inspection exceptions, and capacity reports during regular maintenance. Remove temporary test objects and document why permanent exclusions exist. Export sanitized configuration details for disaster recovery without exposing secrets.

Use these operational recommendations:

• Start with a small set of noncritical VIPs and expand after performance testing.
• Verify certificate chains and private-key matches before enabling live inspection.
• Test TLS 1.2, TLS 1.3, mutual TLS, WebSockets, and long-lived sessions where applicable.
• Monitor inspection capacity separately from ordinary packet-processing capacity.
• Document fail-open, fail-closed, bypass, and certificate-renewal procedures.

A carefully scoped DefensePro deployment can improve visibility into encrypted attacks without turning TLS inspection into an uncontrolled availability risk. Build the policy around known services, protect the keys, test both traffic legs, and retain a clear bypass path for applications that cannot tolerate interception. Apply the configuration in a lab first, then use measured production changes and continuous monitoring to keep encrypted traffic protection reliable.