Sender Policy Framework (SPF) is an open standard that senders can use to publish which IPs are authorized to send email from their domain. SpamHero is compatible with SPF and will usually pose no problems for such senders.
However, if your mail server has an SPF filter enabled, we recommend that you turn it off, because your mail server will see email coming from SpamHero's IPs and bounce messages that come from senders that have SPF enabled on their domain.
Any of the following solutions can be used to resolve SPF delivery problems:
- Turn off the SPF filter on your server.
- White list SpamHero's IPs in your mail server's SPF configuration so that it always allows mail from SpamHero.
- Enable the SPF Workaround option in the SpamHero control panel (under Settings > Filtering policies. See the steps here.)
SpamHero detects bounces caused by SPF filters and automatically re-delivers these messages using a technique that allows us to bypass the SPF filter. However, since the sender still receives a bounce, we still recommend that SPF filters be disabled. For those that want to know, the technique is pretty simple... when an SPF bounce is detected, the message is re-sent to your mail server after modifying the return path to use our server's host name (the "From:" is not touched).
A common mistake we have seen our customers make is to delete their domain's own SPF record in an effort to shut off the SPF filter for their mail server. There is no reason to delete your domain's SPF record as that will have no affect on your incoming email. Your domain's SPF record affects your outbound email only.