The PPLOG script did have blacklisting by ipaddress, however it required hard-coding the ipaddresses into the script. Prit has added a button and a separate file to hold the blacklisted ipaddresses.
This latest PPLOG script is now running on my blog (what you are looking at now).
Note that PPLOG is a very small single Perl script, that prit liked very much and rewrote in PHP, calling it Pritlog. He has added more features, and you can find out about Pritlog here:
Also (note, prit has moved from flat files to Sqlite):
Comments:Posted on 22 Apr 2010, 21:59 by Prit
Barry, Thanks for using the mod. The blacklisting is based on IP address and user name. When blacklisted, any user from the same IP cannot post comments. Also, the same user from a different IP cannot post comments.