Fail2ban: Difference between revisions

Latest revision as of 13:01, 24 March 2023

sudo cp /etc/fail2ban/fail2ban.conf /etc/fail2ban/fail2ban.local

sudo cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

to edit config edit the jail.local file!!!

sudo nano /etc/fail2ban/jail.local

Log Files

sudo nano /var/log/fail2ban.log

Configuration

[sshd]
# To use more aggressive sshd modes set filter parameter "mode" in jail.local:
# normal (default), ddos, extra or aggressive (combines all).
# See "tests/files/logs/sshd" or "filter.d/sshd.conf" for usage example and details.
#mode   = normal
enabled = true
port    = ssh
# initial ban time:
bantime = 1h
# incremental banning:
bantime.increment = true
# default factor (causes increment - 1h -> 1d 2d 4d 8d 16d 32d ...):
bantime.factor = 24
# max banning time = 5 week:
bantime.maxtime = 5w
logpath = %(sshd_log)s
backend = %(sshd_backend)s

unban

fail2ban-client set YOURJAILNAMEHERE unbanip IPADDRESSHERE

The hard part is finding the right jail:

Use iptables -L -n to find the rule name... ...then use fail2ban-client status to get the actual jail names. The rule name and jail name may not be the same but it should be clear which one is related to which.

@@ Line 10: / Line 10: @@
   sudo nano /var/log/fail2ban.log
-==trying to resolve errors:==
+==Configuration==
+ [sshd]
+ # To use more aggressive sshd modes set filter parameter "mode" in jail.local:
+ # normal (default), ddos, extra or aggressive (combines all).
+ # See "tests/files/logs/sshd" or "filter.d/sshd.conf" for usage example and details.
+ #mode   = normal
+ enabled = true
+ port    = ssh
+ # initial ban time:
+ bantime = 1h
+ # incremental banning:
+ bantime.increment = true
+ # default factor (causes increment - 1h -> 1d 2d 4d 8d 16d 32d ...):
+ bantime.factor = 24
+ # max banning time = 5 week:
+ bantime.maxtime = 5w
+ logpath = %(sshd_log)s
+ backend = %(sshd_backend)s
-<poem>
+==unban==
--03-14 19:45:55,363 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -j f2b-recidive
+fail2ban-client set YOURJAILNAMEHERE unbanip IPADDRESSHERE
-iptables -w -F f2b-recidive
-iptables -w -X f2b-recidive -- stdout: b''
--03-14 19:45:55,364 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -j f2b-recidive
-iptables -w -F f2b-recidive
-iptables -w -X f2b-recidive -- stderr: b'iptables: Too many links.\n'
--03-14 19:45:55,365 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -j f2b-recidive
-iptables -w -F f2b-recidive
-iptables -w -X f2b-recidive -- returned 1
--03-14 19:45:55,366 fail2ban.actions        [571]: ERROR   Failed to stop jail 'recidive' action 'iptables-allports': Error stopping action
--03-14 19:45:55,367 fail2ban.jail           [571]: INFO    Jail 'recidive' stopped
--03-14 19:45:56,450 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -m multiport --dports 2222 -j f2b-sshd
-iptables -w -F f2b-sshd
-iptables -w -X f2b-sshd -- stdout: b''
--03-14 19:45:56,451 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -m multiport --dports 2222 -j f2b-sshd
-iptables -w -F f2b-sshd
-iptables -w -X f2b-sshd -- stderr: b'iptables: Too many links.\n'
--03-14 19:45:56,452 fail2ban.action         [571]: ERROR   iptables -w -D INPUT -p tcp -m multiport --dports 2222 -j f2b-sshd
-iptables -w -F f2b-sshd
-iptables -w -X f2b-sshd -- returned 1
--03-14 19:45:56,453 fail2ban.actions        [571]: ERROR   Failed to stop jail 'sshd' action 'iptables-multiport': Error stopping action
--03-14 19:45:56,454 fail2ban.jail           [571]: INFO    Jail 'sshd' stopped
--03-14 19:45:57,452 fail2ban.jail           [571]: INFO    Jail 'sshd-ddos' stopped
--03-14 19:45:57,457 fail2ban.server         [571]: INFO    Exiting Fail2ban
--03-14 19:46:16,950 fail2ban.server         [588]: INFO    Changed logging target to /var/log/fail2ban.log for Fail2ban v0.9.6
--03-14 19:46:16,972 fail2ban.database       [588]: INFO    Connected to fail2ban persistent database '/var/lib/fail2ban/fail2ban.sqlite3'
--03-14 19:46:16,992 fail2ban.jail           [588]: INFO    Creating new jail 'sshd'
--03-14 19:46:17,099 fail2ban.jail           [588]: INFO    Jail 'sshd' uses pyinotify {}
--03-14 19:46:17,200 fail2ban.jail           [588]: INFO    Initiated 'pyinotify' backend
--03-14 19:46:17,203 fail2ban.filter         [588]: INFO    Set jail log file encoding to UTF-8
-</poem>
-steps taken:
+The hard part is finding the right jail:
- sudo apt install python-pyinotify
- sudo nano /etc/fail2ban/jail.local
+Use iptables -L -n to find the rule name...
+...then use fail2ban-client status to get the actual jail names. The rule name and jail name may not be the same but it should be clear which one is related to which.
-changed: <code>backend = auto</code>
-to: <code>backend = pyinotify</code>