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Testing Backup Email Service

Please ensure you have allowed 2 hours to make sure that all of the mail servers have been updated to accept mail with your new configurations. DNS Made Easy operates mail servers in multiple geographic locations so it does take some time to update all of the mail clusters securely.

Possible tests include:

  1. Turn off your mail server temporarily and send yourself an email.
  2. Change the settings in your mail client (such as Outlook) to use the DNS Made Easy mail servers as your SMTP server. Then send yourself an email. The backup mail server will relay the email to the final destination.
  3. If you understand the SMTP protocol you can telnet to the DNS Made Easy mail servers (on port 25) and send yourself an email message.

In this example we will send an email to a user “” and send it from “”. The items in bold are the ones that you would type. You will also want to use the mail servers that were assigned to you. In this example we will just use “” for testing purposes.

# telnet 25
Connected to
Escape character is ‘^]’.
220 ESMTP TiggeeSMTP (1.0.1)
250-SIZE 20240000
mail from: <>
250 Ok
rcpt to: <>
250 Ok
354 End data with <CR><LF>.<CR><LF>
This is a sample email.
250 Ok: queued as 783C7B9E0A8
221 Bye
Connection closed by foreign host.

Debugging possible errors while testing the Backup Email Services

  • Reverse DNS
    • DNS Made Easy makes sure that the connecting system has a reverse DNS setup. Most major ISPs also perform this check as most spammers run their machines on networks that do not have reverse DNS configured.
    • A possible error would be:
      450 Client host rejected: cannot find your hostname, [your IP]
  • Domain Sender
    • The sending domain (usually the domain in the from address) must be a valid domain name and it must resolve or have a DNS configuration to allow a bounce.
    • A possible error would be:
      450 <the from email address >: Sender address rejected: Domain not found
  • FQDN in helo
    • The system name stated in the helo / ehlo must be a fully qualified domain name. In some system configurations this name must also be resolvable. This means that the system must identify itself with a name that is resolvable on the Internet.
    • Possible errors would be:
      504 <hostname>: Helo command rejected: need fully-qualified hostname
      450 <hostname>: Helo command rejected: Host not found
  • RBLs
    • DNS Made Easy does use the following RBLs for your convenience
      • Barracuda
      • Our own custom RBL that we use to list servers that send thousands of spam / UCE/ UBE emails to us in under a 24-hour timeframe.
  • Greylisting- This service is not present on the mail server forwarding servers.
    • DNS Made Easy does use Greylisting on all of our backup email servers to prevent most spam from being routed through our networks. This stops post spammers that use the backup email service as a spam relay into your network.
    • Possible error:
      450 <recipient email>: Recipient address rejected: Policy Rejection: Please try later. Greylisting

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