[Exim] Deny sender where from or reply-to is "*@*.kr"

Hi.

I'm running Exim 4.10 on a Linux RedHat 7.2 box (x86). I love it - it's
really stable and has given us no real problems (it only complaints when
I misconfigure it).

We are getting spammed bad from loads of *@*.kr email addresses. I have
never received a single valid email from a kr domain so I'm happy to
deny /all/ emails from it.

I'm going to implement RBLs soon, but we've just done some other major
stuff and I want to make sure the current setup is working as it should.

So: how do I deny all emails that are from a .kr domain and how do I
deny those that are not from a kr domain but have a reply-to set to a kr
domain.

Thanks in advance,

Erik Enge
Software Engineer
Professional Reviews Inc.