When I give /etc/csf/csf.pl -r , I see lots of lines flushing, then I begin to get the notification emails again, (several emails per day), for example:

Time:     Wed Sep 12 08:39:47 2012 +0800
IP:       221.13.104.162 (CN/China/-)
Failures: 5 (sshd)
Interval: 300 seconds
Blocked:  Permanent Block

Log entries:

Sep 12 08:39:25 MyHost sshd[9677]: Failed password for root from 221.13.104.162 port 51106 ssh2
Sep 12 08:39:28 MyHost sshd[9712]: Failed password for root from 221.13.104.162 port 51690 ssh2
Sep 12 08:39:32 MyHost sshd[9739]: Failed password for root from 221.13.104.162 port 52128 ssh2
Sep 12 08:39:36 MyHost sshd[9778]: Failed password for root from 221.13.104.162 port 52670 ssh2
Sep 12 08:39:40 MyHost sshd[9821]: Failed password for root from 221.13.104.162 port 53155 ssh2

And then after about 30 days, the emails stop coming, it is as if something has filled up, and requires flushing again.

I don't know much about CSF/LFD, but I would have imagined that this would work in a FIFO manner, so it should be able to run indefinitely within finite space.

My /etc/csf/version.txt says 4.83

My cat /proc/version says Linux version 2.6.18-028stab066.8 (root@rhel5-64-build) (gcc version 4.1.2 20070626 (Red Hat 4.1.2-14)) #1 SMP Fri Nov 27 20:19:25 MSK 2009