Rejecting emails based on domain blacklist

[Mark Goodge]

What would be the simplest method in Postfix of implementing an 
equivalent to the exim ACL mentioned in this blog post:

http://blog.hinterlands.org/2013/10/unwanted-email-from-communicado-ltd/
That is, what's the simplest way of rejecting email from a list of 
domains contained within a simple text file that can be updated 
regularly without needing to restart Postfix.

Mark
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My blog: http://mark.goodge.co.uk