Block email faking to be from our domain but coming from outside?

[Alex Neuman van der Hans]

Correct way to do it involves properly implementing SPF. Stops 100% of emails purporting to come from you that don’t. 

That being said, be careful about domains that only Iook like they come from your domain but are carefuIIy constructed. Uppercase i looks like lowercase L. 

> On Jun 8, 2018, at 4:35 AM, Remco Barendse <mailscanner at barendse.to> wrote:
> 
> See more and more messages incoming with fraud attempts. The mail is constructed to look like from someone in our organization sent it and is addressed to people within the organization.
> 
> Is there any way to block email with a sender that pretends to be coming from @myowndomain.com but coming from outside?
> 
> I use Exchange and all real email is coming only from Exchange, never from outside.
> 
> What would be the right way to do it?
> 
> 
> 
> Also, some companies sign incoming email messages with a one liner as the very first line of an email like :
> "THIS EMAIL ORIGINATED FROM OUTSIDE OUR ORGANIZATION"
> 
> How to do that ? I found that MailScanner can sign messages but only at the bottom of an email?
> 
> 
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