SMTP Test

The following checks in SpamExperts's Network Tools, SMTP page can be used to test mail transfer:

  • Sender callout - If you are seeing problems with sender verification, you can see exactly what the sender's mail server responds with when the address is checked
  • Recipient callout - If you are seeing delivery problems, you can see exactly what the destination's mail server responds with when the recipient is specified
  • Open relay check - You can see whether a mail server appears to be an "open relay", accepting mail for any destination
  • Catch-all check - You can see whether a mail server appears to be a "catch-all" for a specified domain, accepting mail for any address at that domain
  • Telnet test - You can check the full SMTP delivery process to a destination, to see exactly how the destination responds in answer to each of the SMTP commands, and the final message content. The tool will go as far as the information provided. If a recipient is not provided, then the connection will end after "MAIL FROM", and if a message is not provided, then the connection will end after "RCPT TO". If you have a message in the DATA section, this will send an email to the specified recipient

    • To test deliverability issues from a specific server in the cluster, or IP assigned to a server, select the relevant IP. If left blank, then one of the control panel IPs will be used.

  1. Login to SpamExperts to the Admin, Domain or Email Level Control Panel
  2. In the right-hand menu, navigate to Continuity > Network Tools
  3. Switch to the SMTP tab

  4. Fill in the SMTP Test Fields
  5. Check the Prefer TLS option to attempt to use STARTTLS to perform the test over a secure connection
  6. Check the Exchange Servers - data only option to use a suitable test message in DATA if the server appears to be a Microsoft Exchange server

    We generally recommend using this setting when completing a Callout check, but note that if the recipient is valid, they will receive a test email message

  7. Click Run

    8. Once run, the results of the SMTP test will appear in the Results box on the page

SMTP Test Fields

Field Description
Hostname

Enter a server hostname here or enter the Envelope sender

Optional: Try all Hosts - if selected, the SMTP check will be executed for all possible destination servers until one succeeds
EHLO Name of the EHLO/HELO that you want to use in the SMTP transaction
Envelope Sender The envelope sender email address to initiate a sender callout
Envelope Recipient

The envelope recipient email address to initiate a recipient callout

Optional: Catch all - Using the Catch all option you can see whether a mail server appears to be a 'catch-all' for a specified domain, accepting mail for any address at that domain.

Data

If you want to send data to the envelope-recipient e.g. the content of the SMTP transaction and not just a callout

Optional: Default Message - If nothing specific is required, use a default message type
Timeout, per SMTP command How long the SMTP command should to last (e.g. for slower mta's there may be a need to set this higher before it times out)

Interface

Choose the IP address or range to complete the verification from.

For example, if you want to do a sender verification check from a certain IP, choose the IP address from those available. If it is the default , then it uses the interfaces server IP/hostname (securemail.management)