High volume of SPF Failed emails

[SprayCan]

Got a problem.

For the past few months now I've had an ever-increasing volume of emails that are blocked from reaching their recipients (my colleages). The reason for every one of these emails, both legitimate and spam, is:

'Sender is forged (SPF Fail)'.

This is becoming a real nuisense (sp?) for my colleagues. Has anyone got any ideas on how I can rectify this problem? Apologies for the lack of information, I'm a bit new at this.

 

[paulha]

What are you using to filter your spam ?

 

[SprayCan]

GFI MailEssentials. I've upgraded to version 11 now, and that seems to have solved the problem.