Skip to content
You are browsing the Kong Gateway documentation archive for version 2.8. This documentation is no longer actively maintained. Please see the latest Kong Gateway documentation.
Kong Logo | Kong Docs Logo
  • Support
  • Community
  • Kong Academy
Get a Demo Start Free Trial
Kong Gateway
2.8.x (latest) LTS
  • Home icon
  • Kong Gateway
  • PDK
  • kong.client.tls
github-edit-pageEdit this page
report-issueReport an issue
  • Kong Gateway
  • Kong Konnect
  • Kong Mesh
  • Kong AI Gateway
  • Plugin Hub
  • decK
  • Kong Ingress Controller
  • Kong Gateway Operator
  • Insomnia
  • Kuma

  • Docs contribution guidelines
  • 2.8.x (latest) (LTS)
  • Newer versions (3.y.x)
  • Archive (3.0.x and pre-2.8.x)
  • Introduction
    • Overview of Kong Gateway
    • Version Support Policy
    • Stages of Software Availability
    • Changelog
  • Install and Run
    • Overview
    • Kubernetes
    • Helm
    • OpenShift with Helm
    • Docker
    • Amazon Linux
    • CentOS
    • Debian
    • RHEL
    • Ubuntu
    • Migrating from OSS to EE
    • Upgrade Kong Gateway
    • Upgrade Kong Gateway OSS
    • Upgrade from 2.8 LTS to 3.4 LTS
  • Get Started
    • Quickstart Guide
      • Configuring a Service
      • Configuring a gRPC Service
      • Enabling Plugins
      • Adding Consumers
    • Comprehensive Guide
      • Prepare to Administer
      • Expose your Services
      • Protect your Services
      • Improve Performance
      • Secure Services
      • Set Up Intelligent Load Balancing
      • Manage Administrative Teams
      • Publish, Locate, and Consume Services
  • Plan and Deploy
    • Running Kong as a Non-Root User
    • Resource Sizing Guidelines
    • Hybrid Mode
      • Deploy Kong Gateway in Hybrid Mode
    • Kubernetes Deployment Options
    • Control Kong Gateway through systemd
    • Performance Testing Framework
    • DNS Considerations
    • Default Ports
    • Licenses
      • Access Your License
      • Deploy Your License
      • Monitor License Usage
    • Security
      • Start Kong Gateway Securely
      • Keyring and Data Encryption
      • Kong Security Update Process
      • Secrets Management
        • Getting Started
        • Advanced Usage
        • Backends
          • Environment Variables
          • AWS Secrets Manager
          • GCP Secret Manager
          • HashiCorp Vault
        • Reference Format
  • Configure
    • Authentication and Authorization
      • Authentication Reference
      • OpenID Connect Plugin
        • OpenID Connect with Curity
        • OpenID Connect with Azure AD
        • OpenID Connect with Google
        • OpenID Connect with Okta
        • OpenID Connect with Auth0
        • OpenID Connect with Cognito
        • OpenID Connect Plugin Reference
      • Allowing Multiple Authentication Methods
      • Auth for Kong Manager
        • Create a Super Admin
        • Configure Networking
        • Configure Kong Manager to Send Email
        • Reset Passwords and RBAC Tokens
        • Configure Workspaces
        • Basic Auth
        • LDAP
        • OIDC
        • Sessions
      • Role-based Access Control (RBAC)
        • Add a Role
        • Add a User
        • Add an Admin
      • Mapping LDAP Service Directory Groups to Kong Roles
    • Configure gRPC Plugins
    • GraphQL Quickstart
    • Logging Reference
    • Network and Firewall
  • Dev Portal
    • Overview
    • Enable the Dev Portal
    • Structure and File Types
    • Portal API Documentation
    • Working with Templates
    • Using the Editor
    • Configuration
      • Authentication
        • Basic Auth
        • Key Auth
        • OIDC
        • Sessions
        • Adding Custom Registration Fields
      • SMTP
      • Workspaces
    • Administration
      • Manage Developers
      • Developer Roles and Content Permissions
      • Application Registration
        • Authorization Provider Strategy
        • Enable Application Registration
        • Enable Key Authentication for Application Registration
        • External OAuth2 Support
        • Set up Okta and Kong for external OAuth
        • Set Up Azure AD and Kong for External Authentication
        • Manage Applications
    • Customization
      • Easy Theme Editing
      • Migrating Templates Between Workspaces
      • Markdown Rendering Module
      • Customizing Portal Emails
      • Adding and Using JavaScript Assets
      • Single Page App in Dev Portal
      • Alternate OpenAPI Renderer
    • Helpers CLI
  • Monitor
    • Kong Vitals
      • Metrics
      • Reports
      • Vitals with InfluxDB
      • Vitals with Prometheus
      • Estimate Vitals Storage in PostgreSQL
    • Prometheus plugin
    • Zipkin plugin
  • Reference
    • Admin API
      • DB-less Mode
      • Declarative Configuration
      • Supported Content Types
      • Information Routes
      • Health Routes
      • Tags
      • Service Object
      • Route Object
      • Consumer Object
      • Plugin Object
      • Certificate Object
      • CA Certificate Object
      • SNI Object
      • Upstream Object
      • Target Object
      • Vaults Beta
      • Licenses
        • Licenses Reference
        • Licenses Examples
      • Workspaces
        • Workspaces Reference
        • Workspace Examples
      • RBAC
        • RBAC Reference
        • RBAC Examples
      • Admins
        • API Reference
        • Examples
      • Developers
      • Consumer Groups
        • API Reference
        • Examples
      • Event Hooks
        • Event Hooks Reference
        • Examples
      • Audit Logging
      • Keyring and Data Encryption
      • Securing the Admin API
    • DB-less and Declarative Configuration
    • Configuration Reference
    • CLI Reference
    • Load Balancing Reference
    • Proxy Reference
    • Rate Limiting Library
    • Health Checks and Circuit Breakers Reference
    • Clustering Reference
    • Plugin Development Kit
      • kong.client
      • kong.client.tls
      • kong.cluster
      • kong.ctx
      • kong.ip
      • kong.log
      • kong.nginx
      • kong.node
      • kong.request
      • kong.response
      • kong.router
      • kong.service
      • kong.service.request
      • kong.service.response
      • kong.table
      • kong.vault
    • Plugin Development Guide
      • Introduction
      • File structure
      • Implementing custom logic
      • Plugin configuration
      • Accessing the datastore
      • Storing custom entities
      • Caching custom entities
      • Extending the Admin API
      • Writing tests
      • (un)Installing your plugin
    • Plugins in Other Languages
    • File Permissions Reference
enterprise-switcher-icon Switch to OSS
On this pageOn this page
  • kong.client.tls.request_client_certificate()
  • kong.client.tls.disable_session_reuse()
  • kong.client.tls.get_full_client_certificate_chain()
  • kong.client.tls.set_client_verify()

kong.client.tls

Client TLS connection module.

A set of functions for interacting with TLS connections from the client.

kong.client.tls.request_client_certificate()

Requests the client to present its client-side certificate to initiate mutual TLS authentication between server and client.

This function requests, but does not require the client to start the mTLS process. The TLS handshake can still complete even if the client doesn’t present a client certificate. However, in that case, it becomes a TLS connection instead of an mTLS connection, as there is no mutual authentication.

To find out whether the client honored the request, use get_full_client_certificate_chain in later phases.

Phases

  • certificate

Returns

  1. true|nil: Returns true if request is received, or nil if request fails.

  2. nil|err: Returns nil if the handshake is successful, or an error message if it fails.

Usage

local res, err = kong.client.tls.request_client_certificate()
if not res then
  -- do something with err
end

kong.client.tls.disable_session_reuse()

Prevents the TLS session for the current connection from being reused by disabling the session ticket and session ID for the current TLS connection.

Phases

  • certificate

Returns

  1. true|nil: Returns true if successful, nil if it fails.

  2. nil|err: Returns nil if successful, or an error message if it fails.

Usage

local res, err = kong.client.tls.disable_session_reuse()
if not res then
  -- do something with err
end

kong.client.tls.get_full_client_certificate_chain()

Returns the PEM encoded downstream client certificate chain with the client certificate at the top and intermediate certificates (if any) at the bottom.

Phases

  • rewrite, access, balancer, header_filter, body_filter, log

Returns

  1. string|nil: Returns a PEM-encoded client certificate if the mTLS handshake was completed, or nil if an error occurred or the client did not present its certificate.

  2. nil|err: Returns nil if successful, or an error message if it fails.

Usage

local cert, err = kong.client.get_full_client_certificate_chain()
if err then
  -- do something with err
end

if not cert then
  -- client did not complete mTLS
end

-- do something with cert

kong.client.tls.set_client_verify()

Overrides the client’s verification result generated by the log serializer.

By default, the request.tls.client_verify field inside the log generated by Kong’s log serializer is the same as the $ssl_client_verify Nginx variable.

Only "SUCCESS", "NONE", or "FAILED:<reason>" are accepted values.

This function does not return anything on success, and throws a Lua error in case of a failure.

Phases

  • rewrite, access, balancer

Usage

kong.client.tls.set_client_verify("FAILED:unknown CA")
Thank you for your feedback.
Was this page useful?
Too much on your plate? close cta icon
More features, less infrastructure with Kong Konnect. 1M requests per month for free.
Try it for Free
  • Kong
    Powering the API world

    Increase developer productivity, security, and performance at scale with the unified platform for API management, service mesh, and ingress controller.

    • Products
      • Kong Konnect
      • Kong Gateway Enterprise
      • Kong Gateway
      • Kong Mesh
      • Kong Ingress Controller
      • Kong Insomnia
      • Product Updates
      • Get Started
    • Documentation
      • Kong Konnect Docs
      • Kong Gateway Docs
      • Kong Mesh Docs
      • Kong Insomnia Docs
      • Kong Konnect Plugin Hub
    • Open Source
      • Kong Gateway
      • Kuma
      • Insomnia
      • Kong Community
    • Company
      • About Kong
      • Customers
      • Careers
      • Press
      • Events
      • Contact
  • Terms• Privacy• Trust and Compliance
© Kong Inc. 2025