Check mail server tls

To check the TLS (Transport Layer Security) configuration of a mail server, you can use various tools and commands. Here are a few methods:

Method 1: Using OpenSSL

You can use OpenSSL to check the TLS configuration of a mail server. Here's an example command:

openssl s_client -connect <mail_server>:25 -starttls smtp

Replace <mail_server> with the hostname or IP address of the mail server. This command will establish a TLS connection to the mail server on port 25 and display the TLS handshake and certificate information.

Method 2: Using Telnet

You can use Telnet to connect to the mail server and check the TLS configuration. Here's an example command:

telnet <mail_server> 25

Replace <mail_server> with the hostname or IP address of the mail server. This command will establish a connection to the mail server on port 25. You can then type STARTTLS to initiate the TLS handshake.

Method 3: Using a mail client

You can also use a mail client like Thunderbird or Microsoft Outlook to check the TLS configuration of a mail server. Here's how:

• In Thunderbird, go to Tools > Account Settings > Server Settings and click on the Edit button next to Server. Then, click on the TLS tab to view the TLS configuration.
• In Microsoft Outlook, go to File > Account Settings > Account and click on the Change button next to More Settings. Then, click on the Advanced tab and scroll down to the Use the following type of encrypted connection dropdown menu to view the TLS configuration.

Common TLS checks

When checking the TLS configuration of a mail server, you should verify the following:

1. Certificate: Check that the mail server is using a valid SSL/TLS certificate. The certificate should be issued by a trusted Certificate Authority (CA) and should match the mail server's hostname.
2. Cipher suite: Check that the mail server is using a secure cipher suite (e.g., TLS 1.2 or higher, with a strong encryption algorithm like AES).
3. Protocol: Check that the mail server is using the correct TLS protocol (e.g., TLS 1.2 or TLS 1.3).
4. Certificate validation: Check that the mail server is validating the certificates of its clients (e.g., email clients).
5. TLS version: Check that the mail server is using a supported TLS version (e.g., TLS 1.2 or TLS 1.3).

By checking these TLS configuration settings, you can ensure that your mail server is secure and compliant with industry standards.