I was getting Ndr's from domains using Spf (by the way we relay through websense) so we have now configured an Spf Dns record to allow mail to be sent from our mail server. This I believe should have fixed the problem and the record is configured as follows:
v=spf1 a mx a:cluster-a.mailcontrol.co
m a:[external hostname] -all
but now when I test it from http://www.openspf.org/Why
I get the following:
The domain [domain name] has authorized [external hostname] (IP Address) to send mail on its behalf, so the message should have been accepted. It is impossible for us to say why it was rejected.
Can anyone help with this please?
Domain with Windows Server 2003 R2 and Exchange 2007
All mail relayed out through smarthost (problem is only with domains that use Spf checks)