If you want to disguise IP addresses in logfiles, there is a fast and simple way to do so with sed. If there is no option to disable logging the full IP address in the application, you could use a cronjob to run this every now and then. It will remove the last decimal of the ip address.

echo 8.8.8.8 | sed -e 's/(([0-9]+.){3})[0-9]+/10/'
8.8.8.0

# The ? in .lo? is for using only files that DO end in .log, and not in .log.gz
sed -i -e 's/(([0-9]+.){3})[0-9]+/10/' /var/log/apache2/*.lo?