You can configure Lighttpd to log the IP’s which accessed the server:
I’m not sure if this is enabled by default, but I guess not, so just do this:
sudo lighttpd-enable-mod accesslog
This enables the logging. The default path of the log should be /var/log/lighttpd/access.log, otherwise you can define a path in your /etc/lighttpd/lighttpd.conf by adding this line:
accesslog.filename = “/var/log/lighttpd/access.log”