Block email from all exept one server

[SajtXL]

Hi all.

Today I have an external spam filtering provider that I let all the mail go through.

Works excellent, the load on my servers and use of bandwidth has decreased strongly.

However, there remains a small problem. Some spammers send messages directly to my server.
Is there any way of blocking all email except from a specific server?

In advance, thanks for your help.

 

[LawsHosting]

Can you provide us with the headers of one of these messages.

 

[nobaloney]

Yes, you can, by rewriting the ACLs.

You should first accept locally-originating email (or else neither scripts nor webmail will work).

Then you should accept authenticated email (if your users will be sending mail through your server).

Then you can deny all other email.

Jeff