Skip to content
2023 API Summit Hackathon: Experiment with AI for APIs (August 28 - September 27) Learn More →
Kong Logo | Kong Docs Logo
search
  • We're Hiring!
  • Docs
    • Kong Gateway
      Lightweight, fast, and flexible cloud-native API gateway
      Kong Konnect
      Single platform for SaaS end-to-end connectivity
      Kong Mesh
      Enterprise service mesh based on Kuma and Envoy
      decK
      Helps manage Kong’s configuration in a declarative fashion
      Kong Ingress Controller
      Works inside a Kubernetes cluster and configures Kong to proxy traffic
      Kong Gateway Operator
      Manage your Kong deployments on Kubernetes using YAML Manifests
      Insomnia
      Collaborative API development platform
      Kuma
      Open-source distributed control plane with a bundled Envoy Proxy integration
  • API Specs
  • Plugin Hub
    • Explore the Plugin Hub
      View all plugins View all plugins View all plugins arrow image
    • Functionality View all View all arrow image
      View all plugins
      Authentication's icon
      Authentication
      Protect your services with an authentication layer
      Security's icon
      Security
      Protect your services with additional security layer
      Traffic Control's icon
      Traffic Control
      Manage, throttle and restrict inbound and outbound API traffic
      Serverless's icon
      Serverless
      Invoke serverless functions in combination with other plugins
      Analytics & Monitoring's icon
      Analytics & Monitoring
      Visualize, inspect and monitor APIs and microservices traffic
      Transformations's icon
      Transformations
      Transform request and responses on the fly on Kong
      Logging's icon
      Logging
      Log request and response data using the best transport for your infrastructure
  • Support
  • Community
  • Kong Academy
Get a Demo Start Free Trial
Kong Gateway
3.2.x
  • Home icon
  • Kong Gateway
  • Production Deployment
  • Networking
  • Troubleshoot PostgreSQL TLS
github-edit-pageEdit this page
report-issueReport an issue
  • Kong Gateway
  • Kong Konnect
  • Kong Mesh
  • Plugin Hub
  • decK
  • Kong Ingress Controller
  • Kong Gateway Operator
  • Insomnia
  • Kuma

  • Docs contribution guidelines
  • 3.4.x (latest)
  • 3.3.x
  • 3.2.x
  • 3.1.x
  • 3.0.x
  • 2.8.x
  • 2.7.x
  • 2.6.x
  • Archive (pre-2.6)
enterprise-switcher-icon Switch to OSS
On this pageOn this page
  • PostgreSQL
    • Could not accept SSL connection
    • Could not load server certificate file
    • Could not access private key file
    • Incorrect private key permissions
    • Failed to verify the SSL certificate
    • Certificate verify failed
    • Certificate authentication failed for user
    • Connection requires a valid client certificate
  • Troubleshooting TLS on Kong Gateway
    • Protocol versions are not a match
    • The server does not support SSL connections
    • Certificate verify failed
    • Connection requires a valid client certificate
    • tlsv1 alert unknown ca
    • Certificate authentication failed for user
You are browsing documentation for an outdated version. See the latest documentation here.

Troubleshoot PostgreSQL TLS

PostgreSQL

Could not accept SSL connection

If you receive either of the following error messages, you are experiencing an issue with mismatched SSL versions.

LOG:  could not accept SSL connection: wrong version number
HINT:  This may indicate that the client does not support any SSL protocol version between TLSv1.1 and TLSv1.1.
LOG:  could not accept SSL connection: unsupported protocol
HINT:  This may indicate that the client does not support any SSL protocol version between TLSv1.2 and TLSv1.3.

In this case, the client is trying to connect to the server using a version of the TLS protocol that is not supported by the server. Check which version PostgreSQL supports and adjust the client-side TLS version.

You can check the TLS version by running the pg_config --configure command.

Kong recommends TLSv1.2 or higher. Lower versions are deprecated and are not considered secure.

Could not load server certificate file

If you are receiving this error message:

FATAL:  could not load server certificate file "server.crt": No such file or directory

The server is unable to find the certificate file. By default, the certificate file should be named server.crt, and it should be placed in the server’s data directory. Other names are allowed, but they should be explicitly specified in the ssl_cert_file.

Could not access private key file

If you are receiving this error message:

FATAL:  could not access private key file "server.key": No such file or directory

The server is unable to find the private key file. By default, the private key file should be named server.key, and it should be placed in the server’s data directory. If you used another naming convention it should be explicitly set using the ssl_key_file parameter in the postgresql.conf file.

Incorrect private key permissions

FATAL:  private key file "/certs/example.com.key" has group or world access
DETAIL:  File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root.

If you receive this error, the permissions for the private key are incorrect. Use the information in the error message to apply the correct permissions to your private key.

Failed to verify the SSL certificate

LOG:  could not accept SSL connection: tlsv1 alert unknown ca

The client has failed to verify the PostgreSQL server certificate. To resolve this issue, make sure that the certificate matches the one applied to Kong Gateway.

Certificate verify failed

LOG:  could not accept SSL connection: certificate verify failed

The PostgreSQL server failed to verify the client certificate. You can fix this by verifying that the server provided in the ssl_ca_file parameter in postgres.conf is trusted by the CA.

Certificate authentication failed for user

LOG:  provided user name (kong) and authenticated user name (foo@example.com) do not match
FATAL:  certificate authentication failed for user "kong"

This error message happens when the client certificate doesn’t match the username specified in the database.

Connection requires a valid client certificate

FATAL:  connection requires a valid client certificate

This error occurs when the PostgreSQL server requires a client certificate for authentication, but the client, in this case Kong Gateway, was unable to provide a valid certificate. For this type of error, check if pg_ssl_cert and pg_ssl_cert_key are correctly set in kong.conf.

Troubleshooting TLS on Kong Gateway

Protocol versions are not a match

If you receive either of the following error messages:

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: tlsv1 alert protocol version
Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: unsupported protocol

The server and client versions are not in sync. Check the version that the PostgreSQL server is using and adjust the Kong Gateway version accordingly.

The server does not support SSL connections

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: the server does not support SSL connections

This error occurs when SSL is not supported by PostgreSQL. Configure PostgreSQL according to the configuration instructions.

Certificate verify failed

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: certificate verify failed

This error occurs when Kong Gateway fails to verify the PostgreSQL server certificate. Ensure that the PostgreSQL server has configured a trusted certificate and the corresponding CA chain is correctly set in lua_ssl_trusted_certificate within kong.conf.

Connection requires a valid client certificate

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: FATAL: connection requires a valid client certificate

Kong Gateway requires a client certificate for authentication, but the client was unable to provide a valid certificate.

This error occurs when the PostgreSQL server requires a client certificate for authentication, but the Kong Gateway is unable to provide a valid certificate. For this type of error, check if pg_ssl_cert and pg_ssl_cert_key are correctly set in kong.conf.

tlsv1 alert unknown ca

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: tlsv1 alert unknown ca

The PostgreSQL server failed to verify the client certificate. Use a client certificate which is trusted by the CA set in ssl_ca_file within postgres.conf.

Certificate authentication failed for user

Error: [PostgreSQL error] failed to retrieve PostgreSQL server_version_num: FATAL: certificate authentication failed for user "kong"

The common name of the client certificate doesn’t match the username set in the database. Add a username mapping in pg_ident.conf as described in the PostgreSQL configuration instructions.

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
    THE CLOUD CONNECTIVITY COMPANY

    Kong powers reliable digital connections across APIs, hybrid and multi-cloud environments.

    • Company
    • Customers
    • Events
    • Investors
    • Careers Hiring!
    • Partners
    • Press
    • Contact
  • Products
    • Kong Konnect
    • Kong Gateway
    • Kong Mesh
    • Get Started
    • Pricing
  • Resources
    • eBooks
    • Webinars
    • Briefs
    • Blog
    • API Gateway
    • Microservices
  • Open Source
    • Install Kong Gateway
    • Kong Community
    • Kubernetes Ingress
    • Kuma
    • Insomnia
  • Solutions
    • Decentralize
    • Secure & Govern
    • Create a Dev Platform
    • API Gateway
    • Kubernetes
    • Service Mesh
Star
  • Terms•Privacy
© Kong Inc. 2023