Debian & Ubuntu style

get installed packages:

dpkg --get-selections > dpkg_selection

set & install packages from file:

dpkg --set-selections < dpkg_selection

aptitude install

# or:
apt-get -u dselect-upgrade

date

date --set 1998-11-02 
date --set 21:08:0

dpkg-reconfigure tzdata

apt-get install locales
dpkg-reconfigure locales
locale

debugging:

if the service doesn't start

for some useful error messages:

fail2ban-client -x start

too much cpu / ram usage maybe a problem with /etc/localtime

trace which files are opened / closed all the time by one of the server threads:

strace -f -p <various pids of fail2ban processes

try to delete the database in /var/lib/fail2ban