How to spf test internal mail

SPF (Sender Policy Framework) is a security protocol that helps prevent email spoofing by verifying the authenticity of an email sender's domain. To test an internal mail server's SPF configuration, you can follow these steps:

Method 1: Using a Mail Client

  1. Set up a mail client (e.g., Microsoft Outlook, Mozilla Thunderbird) on your local machine.
  2. Configure the mail client to send an email from your internal mail server's domain (e.g., example.com).
  3. Use a tool like dig or nslookup to query the SPF record for your internal mail server's domain. You can do this by running a command like dig +short example.com TXT or nslookup -type=txt example.com.
  4. Verify that the SPF record includes the IP addresses of your internal mail server's mail exchanger (MX) records.
  5. Send the email from your mail client and check the email headers for the Authentication-Results header. This header should include information about the SPF check, such as whether it passed or failed.

Method 2: Using a Command-Line Tool

  1. Install a command-line tool like spfquery or spf-test on your system.
  2. Use the tool to query the SPF record for your internal mail server's domain. For example, you can run a command like spfquery example.com or spf-test example.com.
  3. Verify that the SPF record includes the IP addresses of your internal mail server's MX records.
  4. Use the tool to simulate an email send from your internal mail server's domain. For example, you can run a command like spfquery -s example.com or spf-test -s example.com.
  5. Check the output of the command to see if the SPF check passed or failed.

Method 3: Using an Online SPF Tester

  1. Find an online SPF tester tool, such as the one provided by Kitterman or the SPF Tester.
  2. Enter your internal mail server's domain and the IP address of your mail server's MX record.
  3. Click the "Test" button to simulate an email send from your internal mail server's domain.
  4. Check the output of the test to see if the SPF check passed or failed.

In all cases, if the SPF check fails, it may indicate that your internal mail server's configuration is not correctly set up or that there is a misconfiguration in your DNS records. You can use the output of the test to troubleshoot and resolve any issues.