fail2ban.filter : INFO Log rotation detected for /var/log/mail.log

[dynamind]

Hello,

in the backend the fail2ban log shows:

2011-07-17 07:55:51,688 fail2ban.server : INFO Changed logging target to /var/log/fail2ban.log for Fail2ban v0.8.4-SVN
2011-07-17 07:55:53,674 fail2ban.filter : INFO Log rotation detected for /var/log/syslog
2011-07-17 07:55:54,502 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 07:55:54,509 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 07:55:54,525 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 07:55:54,525 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 07:55:54,526 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 07:55:54,681 fail2ban.filter : INFO Log rotation detected for /var/log/auth.log
2011-07-17 07:56:01,688 fail2ban.filter : INFO Log rotation detected for /var/log/auth.log
2011-07-17 08:00:02,760 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 08:00:02,761 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 08:00:02,778 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 08:00:02,778 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log
2011-07-17 08:00:02,779 fail2ban.filter : INFO Log rotation detected for /var/log/mail.log

what does it mean?