How curl Command is useful for SSL/TLS connections In Linux

curl-ssl-request

The curl command is useful for SSL/TLS connections because it supports a wide range of SSL/TLS versions, ciphers, and protocols. This makes it a flexible tool for debugging SSL/TLS connections and ensuring that they are secure and compliant with best practices. Here are some examples of how to use curl for SSL/TLS connections:

Checking SSL/TLS certificate details:

The curl command can be used to retrieve SSL/TLS certificates and print their details. For example:

curl -v https://example.com

This will send an HTTP GET request to https://example.com and print verbose output, including the SSL/TLS certificate chain, expiration date, issuer, and more.

Specifying SSL/TLS version:
The curl command allows you to specify the SSL/TLS version to use. For example:

curl --tlsv1.2 https://example.com

This will send an HTTP GET request to https://example.com using the TLSv1.2 protocol.

Specifying SSL/TLS cipher:
The curl command allows you to specify the SSL/TLS cipher to use. For example:

curl --ciphers ecdhe_rsa_aes_256_gcm_sha384 https://example.com

This will send an HTTP GET request to https://example.com using the ECDHE-RSA-AES256-GCM-SHA384 cipher.

Verifying SSL/TLS peer:
The curl command can be used to verify the SSL/TLS peer's certificate. For example:

curl --cacert /path/to/ca.pem https://example.com

This will send an HTTP GET request to https://example.com and verify that the server's SSL/TLS certificate is signed by a trusted CA.

Overall, the curl command is a powerful tool for debugging SSL/TLS connections and ensuring that they are secure and compliant with best practices. By using curl to check SSL/TLS certificate details, specify SSL/TLS version and cipher, and verify SSL/TLS peers, you can help ensure that your SSL/TLS connections are secure and free of vulnerabilities.