Check SSL/TLS Versions on macOS and Windows

In this guide, we’ll show you how to use the openssl tool on both macOS and Windows to check SSL/TLS versions and cipher suites — and even test remote servers.

SSL/TLS is the backbone of secure internet communication. Whether you’re a developer, sysadmin, or security enthusiast, knowing what versions and cipher suites your system supports is crucial for ensuring secure connections.

For example, if you want to build a website, you need to setup SSL/TLS to keep your website secure. For how to build a website from scratch you can refer to the series: Build a Website from Scratch – Step by Step Guide for Beginners

🛠 What You’ll Need to Check SSL/TLS Versions

A terminal (macOS Terminal or Git Bash on Windows)
openssl installed (comes preinstalled on macOS; included with Git Bash for Windows users)
Internet access

✅ Check SSL/TLS Versions in Local OS

Run the following command in your terminal:

openssl ciphers -v | awk '{print $2}' | sort | uniq

What it does:

Lists all cipher suites and extracts their associated SSL/TLS version
Sorts and removes duplicates to show supported protocol versions (e.g., TLSv1.2, TLSv1.3)

🔒 List All Supported Cipher Suites

Use this command:

openssl ciphers -v | column -t

This displays all supported cipher suites in a readable table format, showing:

Cipher name
Protocol version
Key exchange algorithm
Authentication method
Encryption and MAC

🌐 Check SSL/TLS Versions of a Remote Server

Want to see what a server supports? Use:

openssl s_client -connect www.example.com:443 -tls1_2

Replace www.example.com with your target domain or IP address. You can also test other versions:

openssl s_client -connect www.example.com:443 -tls1_1
openssl s_client -connect www.example.com:443 -tls1

These tests help verify if the remote server supports specific TLS versions.

💻 macOS and Windows Compatibility

macOS:

Open Terminal
Run the same commands as above
openssl is typically preinstalled

Windows:

Install Git for Windows if not already installed
Launch Git Bash
Run the same commands (Git Bash includes openssl)

Alternatively, install openssl manually or use Windows Subsystem for Linux (WSL) if you’re on Windows 10/11.

🧪 Bonus: Check OpenSSL Version

Check your local OpenSSL version (which determines supported TLS versions):

openssl version

If needed, upgrade to a newer version to support TLS 1.3.

🔚 Conclusion

Checking supported SSL/TLS versions and cipher suites is a straightforward but powerful way to verify your system’s cryptographic capabilities and troubleshoot secure connections. With just a few openssl commands, you can inspect both local and remote configurations on macOS and Windows.

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