So!,
My nagios was returning a CRITIAL error on one of my servers…
CRITICAL | sd-XXXX.host.net | (Return code of 255 is out of bounds)
and httpd server wasn’t responding….
I think that problem was on IPTABLES / FAIL2BAN ban list. I had 702 banned IPs…
After I clean them up, everything went okay!
I was playing hard with them… my bantime was 3600000 (41d) and my findtime was 60000 (16h)…