Overview

Check SMTP was created mostly to make our lives a little easier, from time to time we will be asked to track down faults on mail servers and find ourselves running the same tests over and over again. So we though, if we're having to do this so will a lot of other people and presto! Check SMTP is born. The website runs through an extensive check of an SMTP service, this includes checking MX Records, DNS black list status, PTR records and querying the server via SMTP.

What would normally take us the better part of half an hour usually completes within 2-3 seconds using Check SMTP. The tool is free for anyone to use, we hope you find it useful.

Technical Brief

Check SMTP was written in PHP, it has a custom SMTP connector which does not send mail itself but tests each stage an SMTP connector for a mail server would go through while sending email. Results are stored in MySQL for future reference.

Website Features

This tool goes through a full check of the mail server's DNS settings, Black list status and SMTP responses from all of the mail servers configured in the MX records. It generates a report based on the responses and will pick up on some even very minor issues, such as suspect PTR records which may cause Anti-Spam software to reject email.
Upon finding an error the server report links to a host of pages explaining the fault in detail and giving some information on how to correct the fault. Links back to the report are provided for future reference of the server owner.