SPF check failed: Not Permitted

[nuclearsiloman]

A client sent me an email today and recieved the following error:

Failed Recipient: kevin@nuclearsiloman.com
Reason: Remote host said: 550 Recipient refused. SPF check failed: Not Permitted.

What does this exactly mean and why am I getting it?

Thanks.

[rob]

Basically they sent a mail from a IP that wasn't permitted by there email domain, and you have SPF filtering enabled. The solution to this is either your customer uses the real SMTP servers of there domain (or if they are an adminstator of that domain, check the SPF records are setup correctly) or you can simply white list there email address in the SPAM filtering options.