What is fail2ban ?

Fail2ban is an intrusion prevention software framework which protects computer servers from brute-force attacks. Written in the Python programming language, it is able to run on POSIX systems that have an interface to a packet-control system or firewall installed locally, for example, iptables or TCP Wrapper.

(Definition from wikipedia -

Why do I need to install this fail2ban's filter ?

To protect your seafile website against brute force attemps. Each time a user/computer tries to connect and fails 3 times, a new line will be write in your seafile logs (seahub.log).

Fail2ban will check this log file and will ban all failed authentications with a new rule in your firewall.


Copy and edit jail.local file

WARNING: this file may override some parameters from your jail.conf file

Edit jail.local with :

  • ports used by your seafile website (e.g. http,https) ;
  • logpath (e.g. /home/yourusername/logs/seahub.log) ;
  • maxretry (default to 3 is equivalent to 9 real attemps in seafile, because one line is written every 3 failed authentications into seafile logs).

Create the file jail.local in /etc/fail2ban with the following content:

# All standard jails are in the file configuration located
# /etc/fail2ban/jail.conf

# Warning you may override any other parameter (e.g. banaction,
# action, port, logpath, etc) in that section within jail.local

# Change logpath with your file log used by seafile (e.g. seahub.log)
# Also you can change the max retry var (3 attemps = 1 line written in the
# seafile log)
# So with this maxrety to 1, the user can try 3 times before his IP is banned


enabled  = true
port     = http,https
filter   = seafile-auth
logpath  = /home/yourusername/logs/seahub.log
maxretry = 3

Create the fail2ban filter file seafile-auth.conf in /etc/fail2ban/filter.d with the following content:

# Fail2Ban filter for seafile


# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf


_daemon = seaf-server

failregex = Login attempt limit reached.*, ip: <HOST>

ignoreregex = 

# DEV Notes:
# pattern :     2015-10-20 15:20:32,402 [WARNING] seahub.auth.views:155 login Login attempt limit reached, username: <user>, ip:, attemps: 3
#        2015-10-20 17:04:32,235 [WARNING] seahub.auth.views:163 login Login attempt limit reached, ip:, attempts: 3

Restart fail2ban

Finally, just restart fail2ban and check your firewall (iptables for me) :

sudo fail2ban-client reload
sudo iptables -S

Fail2ban will create a new chain for this jail. So you should see these new lines :

-N fail2ban-seafile
-A fail2ban-seafile -j RETURN


To do a simple test (but you have to be an administrator on your seafile server) go to your seafile webserver URL and try 3 authentications with a wrong password.

Actually, when you have done that, you are banned from http and https ports in iptables, thanks to fail2ban.

To check that :

on fail2ban

denis@myserver:~$ sudo fail2ban-client status seafile
Status for the jail: seafile
|- filter
|  |- File list:    /home/<youruser>/logs/seahub.log
|  |- Currently failed:    0
|  `- Total failed:    1
`- action
   |- Currently banned:    1
   |  `- IP list:
   `- Total banned:    1

on iptables :

sudo iptables -S

-A fail2ban-seafile -s -j REJECT --reject-with icmp-port-unreachable

To unban your IP address, just execute this command :

sudo fail2ban-client set seafile unbanip

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