13 SMTP Tools to Diagnose and Test Email Security
https://geekflare.com/smtp09.12.2021 · Test and diagnose your server security with MxToolbox. All you need to do is enter your mail server address and hit the button next to the field. This test connects your mail server through SMTP and performs an Open Relay Test. This way, the tool helps you verify if the server includes a reverse DNS or PTR record.
Microsoft Remote Connectivity Analyzer
testconnectivity.microsoft.comThis test walks through the steps Outlook uses to connect from the internet. It tests connectivity using both the RPC over HTTP and the MAPI over HTTP protocols. Inbound SMTP Email This test walks through the steps an Internet email server uses to send inbound SMTP email to your domain. Outbound SMTP Email