grpc_ssl_crl
The grpc_ssl_crl directive specifies a Certificate Revocation List (CRL) file for gRPC SSL connections in NGINX.
Description
The grpc_ssl_crl directive is used in NGINX configurations to define a Certificate Revocation List (CRL) file, which the server utilizes to confirm the validity of client SSL certificates during gRPC connections. This is particularly important in ensuring a secure communication channel by enabling the server to reject any certificates that have been revoked before their expiration date. The directive is applicable in the http, server, and location contexts, allowing for flexibility in scoping the settings for different sections of a configuration.
When a client attempts to connect to the server, NGINX will refer to the specified CRL file to perform checks against the certificates presented by clients. If a client's certificate is found in the CRL, NGINX will deny the connection, enhancing security by ensuring that revoked certificates cannot be used to establish trust. It is critical to keep the CRL file updated to reflect the current status of certificates, commonly obtained from a Certificate Authority (CA) that manages the signatures and revocations.
This directive accepts one argument, which points to the path of the CRL file, and it must be used in conjunction with other SSL directives, such as ssl_certificate and ssl_certificate_key, as part of a complete gRPC SSL configuration.
Config Example
server {
listen 443 ssl;
ssl_certificate /etc/ssl/certs/server.crt;
ssl_certificate_key /etc/ssl/private/server.key;
grpc_ssl_crl /etc/ssl/crl/my_crl.pem;
}
Ensure that the CRL file is correctly formatted and accessible by the NGINX worker processes, or it may lead to errors while starting NGINX.
If the CRL file is too large, it may impact performance during client connection checks; consider the size and frequency of updates.