Question : Email bounces back with  550 5.7.1 SPF unauthorized mail is prohibited

Hello, I have a client trying to email my boss and keeps coming back with the error below. It looks like its on our part but not sure how to fix it. I researched it but found pretty much nothing. Our email is hosted with GoDaddy and then we have Postini as our Spam Filtering. I looked for any SPF settings on Postini but did not see anything. Thanks for any help.

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The original message was received at Thu, 20 Aug 2009 11:33:49 -0500 (CDT)
from mithril@localhost

   ----- The following addresses had permanent fatal errors -----

    (reason: 550 5.7.1 SPF unauthorized mail is prohibited.)

   ----- Transcript of session follows -----
... while talking to example.com.s7a1.psmtp.com.:
>>> DATA
<<< 550 5.7.1 SPF unauthorized mail is prohibited.
554 5.0.0 Service unavailable

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Answer : Email bounces back with  550 5.7.1 SPF unauthorized mail is prohibited

It sounds like they have an SPF record setup for their domain, and you are checking the list and finding that the sender is using an IP address that is not listed in their own 'Allow' list.

Shaun