openssl s_client

openssl s_client is a command-line tool provided by the OpenSSL library for establishing a secure SSL/TLS connection to a server. It can be used to connect to various SSL/TLS-enabled services such as HTTPS, SMTPS, IMAPS, and POP3S.

The s_client tool can be used to perform various tasks such as:

1. Testing SSL/TLS connections to servers
2. Verifying SSL/TLS certificate chains
3. Debugging SSL/TLS issues
4. Retrieving SSL/TLS certificate information
5. Sending SSL/TLS requests to servers

To use openssl s_client, you need to have OpenSSL installed on your system. The basic syntax for using the s_client tool is as follows:

openssl s_client -connect <host>:<port>

For example, to connect to an HTTPS server running on port 443, you can use the following command:

openssl s_client -connect example.com:443

The s_client tool will establish a secure SSL/TLS connection to the server and display various information about the connection, including the SSL/TLS certificate chain and any errors or warnings encountered during the connection process