Home | Sitemap | Recent Changes | Login

SPF Logo

Sender Policy Framework


Why did SPF cause my mail to be rejected?

What is SPF?

SPF is an extension to Internet e-mail. It prevents unauthorized people from forging your e-mail address (see the introduction). But for it to work, your own or your e-mail service provider's setup may need to be adjusted. Otherwise, the system may mistake you for an unauthorized sender.

Note that there is no central institution that enforces SPF. If a message of yours gets blocked due to SPF, this is because (1) your domain has declared an SPF policy that forbids you to send through the mail server through which you sent the message, and (2) the recipient's mail server detected this and blocked the message.

An SPF-enabled mail server rejected a message that claimed an envelope sender address of x@4html.com.

An SPF-enabled mail server received a message from that claimed an envelope sender address of x@4html.com.

The domain 4html.com has not published an SPF policy. It is possible that the receiving mail server refuses all mail from domains that do not have an SPF policy.

How can I reference this web page for explaining SPF results?

This web page is a public service of the SPF project. SPF implementations can (and do) use it to help explain the results of SPF checks by presenting to users a parameterized link to this page. See the "Why?" page documentation for details on how this works.

Edit text of this page | View other revisions
Last edited 2008-04-04 13:27 (UTC) by Frank Ellermann (diff)