You are probably visiting this page because a message was blocked by our inbound mail server software with an SPF error along the lines of does not pass SPF checks for

The message was blocked because of a misconfiguration in the sender's e-mail system. The example error above could be explained as; the sending server was not allowed to send e-mail as according to's SPF settings.

How you should deal with this depends on who you are;

  • If you are the sender of the original e-mail ( in the example above) you should contact your administrator (organization's IT department), because it's most likely your fault
  • If you were the intended recipient of the original e-mail or user of the anti-spam email gateway system that blocked it, you don't need to do anything at all; it's most likely not your fault

Long answer

SPF (Sender Policy Framework) is an email validation system designed to prevent email spam by detecting email spoofing, a common vulnerability, by verifying sender IP addresses.

In other words, the sender ( in the example above) specifies in his domain's DNS server which IP addresses that the company uses for sending e-mail. If someone tries to send (spoof) an e-mail from an IP address not listed in the DNS ( in the example above) the message should be rejected with our email spoofing protection.

As a consequence, the owner of an anti-spam filtering service that receives an e-mail that violates SPF shouldn't do anything to resolve this; it's the sender's responsibility.

You can check the IP Addresses / Servers that are permitted to send email for a domain by using

Resolution Path

If the sender ( did not have ANY SPF records defined we would not be failing them. However they have taken the time to configure SPF and we will honor their configurations. Please contact the sender of the message and have them adjust their SPF records to include the failing IP address.