I just discovered that my Apache 2.2.8 just logs in his access_log the string plesklog
since a few weeks. Normally it looks like that
www.xxx.yyy.zzz - - [19/Jul/2013:04:37:32 +0600] "GET /infos.html HTTP/1.1" 200 12371 "http://www.yahoo.com/" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:22.0) Gecko/20100101 Firefox/22.0"
Currently it looks like that:
plesklog
plesklog
plesklog
plesklog
plesklog
[...]
My apache2.conf looks like that:
[...]
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %T %{mod_php_memory_usage}n" combined
LogFormat "%h %l %u %t \"%r\" %>s %b %T %{mod_php_memory_usage}n" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent
[...]