hosts.deny: how do i test to see if hosts.deny is working

I am trying to block scraper sites from accessing my sites.
I have put a bunch ip addresses in my hosts.deny and I'm not sure if
they've blocked anything.

Then I put my own IP address into the hosts.deny to see if I could
block myself. that didn't work.

I would like to know if there is a log file or some other way to
verify that IP's that I've designated in hosts.deny are actually
getting blocked.

Many thanks.

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