Where is this SPF problem occuring

exchange-2003spf

Inbound mail to a specific user is been forwarded to his external mailbox at another domain. Add mails are routed correctly with the exception of one domain. When mail are sent to users of my domain, including that user, the mails are delivered to everyone except him…as the mail admin I am getting the message

The following recipient(s) cannot be
reached:

  usermailbox on 1/10/2011 1:27 PM
        There was a SMTP communication problem with the

recipient's email server. Please
contact your system administrator.
email.speedimpex.com #5.5.0 smtp;587 someone@somedomain.co.uk sender domain does not match SPF
records>

I am sure this has nothing to do with my mail server, however, can someone confirm?

Best Answer

You are trying to forward emails from a domain that has SPF records, but that domain does not list your server as a valid source of email for that domain.

Your choices are:

  1. Contact somedomain.co.uk and tell them you're forwarding their mail and want to be added to their SPF record.
  2. Contact the "external mailbox at another domain" and tell them you're forwarding email to one of their users and to whitelist you in their SPF checking.
  3. Use Sender Rewriting Scheme on your server to reflect that you are resending this mail from the original sender.
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