I stumbled onto this example for banning access from a troublesome domain.
I haven’t tried it and there may be a down side I don’t know about, but it looks useful although it can tricky to determine the real domain of a trickster. (The domains listed are just examples -- you’d need to put in the domains of people that are annoying you.)
(add to .htaccess file)
## USER IP BANNING
<Limit GET POST>
order allow,deny
deny from 42.12.5.34
deny from 193.110.145.185
deny from 212.173.53.
deny from 69.242.
allow from all
</Limit>
Bob
Note that if you put enough stuff in your .htaccess file, it will eventually impact performance of your site as Apache has to parse the file for every request that it gets
