As the name implies, DevNullSmtp is a dummy SMTP server that can be used for testing purposes. By default, Emails sent to DevNullSmtp are lost. It can be used to troubleshoot email related problems


  • Click here to download this tool.
  • Extract the zipped file in the same folder where you have installed Xeams
  • Double click DevNullSmtp.bat to run it
  • Specify a port number and click Start Server
  • By default, DevNullSmtp will run as an open relay - meaning it will accept messages for every domain and users.
  • Specify desired domain names in the text box below to restrict DevNullSmtp to certain domains
  • Specify complete email addresses to restrict recipients - meaning DevNullSmtp will only accept messages for these individuals

How it works

  • The screenshot on the right shows DevNullSmtp running on port 25 and accepts messages for and
  • The log shows an incoming email that was supposed to be delivered to It was denied by DevNullSmtp is not configured to accept emails for that domain.
  • Check Save incoming messages to box and specify a path on the local machine if you want to save incoming messages.

This version of DevNullSmtp is newer than the version found on