====== Fail2ban ======
ban hosts that cause multiple authentication errors
===== Installation from git =====
Version included in wheezy repository (0.8.6) has serious issues with timezones and other bugs, so you would like to use last version from git repository
  - clone repository<code bash>
git clone https://github.com/fail2ban/fail2ban.git</code>
  - change directory and install the app<code bash>
cd fail2ban
python setup.py install</code>
  - copy config files<code bash>
cp config/* /etc/fail2ban/</code>
  - print iptables version<code bash>iptables --version</code>
  - if iptables version <1.4.20 edit the /etc/fail2ban/action.d/iptables-common.conf and set locking opt to empty string: <code>lockingopt =</code>
  - create startup script and start the service<code bash>
cp files/debian-initd /etc/init.d/fail2ban
update-rc.d fail2ban defaults
service fail2ban start</code>
  * NOTE: installation script registers the app to python package system so uninstall (in case you want to switch back to distribution package) is as easy as <code>pip uninstall fail2ban</code>

====== Cleaning/shrinking the sqlite3 file =======
    DELETE FROM bans WHERE DATE(timeofban, 'unixepoch') < '2020-01-01'; VACUUM;


====== Asterisk ======
change default context in /etc/fail2ban/filter.d/asterisk in following line <code>
^(%(__prefix_line)s|\[\]\s*)%(log_prefix)s Call from '[^']*' \(<HOST>:\d+\) to extension '\d+' rejected because extension not found in context 'default'\.$</code>