To check the TLS version, you can use a network analysis tool like Wireshark. Here’s a breakdown of how to do it:
Checking TLS Version Using Wireshark
Wireshark is a powerful, free, and open-source packet analyzer that lets you capture and inspect network traffic. It allows you to see the details of each packet exchanged, including the TLS protocol version.
Here’s the step-by-step process as per the reference:
- Start Wireshark: Begin by opening Wireshark on your desktop client.
- Set a Host Filter: Filter the captured packets by specifying the Server IP address as the Host filter. This isolates the communication between your client and the server.
- Apply a Display Filter: Use the display filter
tcp.port == 7001 && tls.to filter traffic on TCP port 7001 (replace 7001 with the actual port if different) and focus on the TLS handshake packets. Thetls.part of the filter will narrow the display down to TLS handshake packets which contain the TLS version information. - Check the Protocol Column: Look at the "Protocol" column in the Wireshark output. If you see "TLS," it confirms that TLS encryption is being used.
- Inspect TLS Handshake: To see the exact TLS version, select a TLS handshake packet (usually a "Client Hello" or "Server Hello" message) and go to the "Transport Layer Security" section. The negotiated TLS version will be displayed in the packet details.
Practical Insights
- Understanding Handshake Messages: Pay close attention to the Client Hello and Server Hello messages. These initial handshake messages are where the TLS version negotiation takes place. The client proposes the versions it supports and the server picks the mutually supported version.
- Filtering by IP and Port: Correct filtering using the server IP address as the host filter and the TCP port ensures that you are only looking at the relevant traffic for your analysis.
- Alternative Display Filters: You might need to modify the display filter based on your specific network environment. For example, if you know the server communicates on a different port, adjust
tcp.port == 7001accordingly.
Example of TLS Protocol versions
Here's what you might see in the Wireshark packet details, displaying different TLS versions:
| TLS Version | Description |
|---|---|
| TLSv1.0 | An older version of TLS |
| TLSv1.1 | A slightly improved version over TLS 1.0 |
| TLSv1.2 | More secure version used widely |
| TLSv1.3 | The latest and most secure TLS version |
Conclusion
Using Wireshark with the correct filters is an effective method to identify the TLS version being used in a network connection, as demonstrated by the provided steps.
