Difference between revisions of "FAQ english"

From Fail2ban
Jump to: navigation, search
(Configuration)
(Undo revision 2379 by 93.174.93.200 (Talk))
Line 1: Line 1:
comment3
+
== '''Configuration''' ==
http://7.fortor.dvrdns.org/tdp2w2.html how to make blogspot
+
 
http://3.host.is-a-geek.org/xf72.html costochondritis how long does it last
+
=== What is the main configuration file for {{Fail2ban}}? ===
http://7.webius.servebbs.com/xjjntz.html worlds smallest website
+
 
http://7.hoolpy.dyn-o-saur.com/daq9d64.html how to apply hot fix crystals
+
{{Fail2ban}} configuration process is rather simple. There is only one configuration file, where {{Fail2ban}} can be fully configured, this file is located at:
http://2.jonny.dnsalias.com/cilqtw.html better home and garden patio furniture
+
<tt>/etc/fail2ban/fail2ban.conf</tt>
http://3.hoolpy.dyn-o-saur.com/hi5u7w.html video gratuit sur internet
+
 
http://6.host.is-a-geek.org/iem8vba.html digi makeover game
+
You are able to edit this file using any editor you want: vim, emacs, joe, ae...
http://4.hoolpy.dyn-o-saur.com/u21hzb.html how to clear temporary files
+
 
http://10.webius.servebbs.com/rm40d.html wholesale glycerine soap
+
Configuration file must be edited by '''root'''.
http://4.host.is-a-geek.org/71wnj.html france funny facts
+
 
http://3.mywy.homeip.net/z1en.html buying resale timeshares
+
=== How can {{Fail2ban}} be configured? ===
http://3.hoolpy.dyn-o-saur.com/h2pxou.html south park san diego homes
+
 
http://10.mywy.homeip.net/sg4r0w.html guitar parts pickups
+
This step is fully detailed at [[HOWTOs]] chapter
http://8.fortor.dvrdns.org/lji1.html timetable for ssc exams 2007
+
 
http://9.hoolpy.dyn-o-saur.com/245o3k.html alanda club marbella apartments
+
=== Can I exclude failed logins for selected users from resulting in a ban? ===
http://1.webius.servebbs.com/q9uluh0.html how to find trade in value
+
 
http://4.host.is-a-geek.org/6om3.html food front portland
+
(I don't know, perhaps that's a feature request.)
http://2.webius.servebbs.com/jj7wh.html fast multiresolution image
+
 
http://4.webius.servebbs.com/g09m.html black and white floral dresses
+
Edit: Cause fail2ban didn't know anything of the username format logged in the specific file(s) (if usernames even get logged), it is only possible to exclude selected users in the regex of the service section.
http://5.webius.servebbs.com/fvrb66.html home show secaucus nj
+
 
http://10.jonny.dnsalias.com/pzv3i3b.html lussino 4080 ice cream maker
+
=== Is there a way to have bans persist over restarts and log rotation? ===
http://7.jonny.dnsalias.com/b9a4zs9.html how to pray catholic
+
http://9.wifin.shacknet.nu/upuids.html steps to how to dance
+
http://10.hoolpy.dyn-o-saur.com/3q62pd.html informacion sobre la anorexia
+
http://10.mywy.homeip.net/wa7vv.html hollywood video augusta
+
http://4.dynos.gotdns.com/fipy6n.html biblical world history timeline
+
http://11.host.is-a-geek.org/hrr5a.html of prostate surgery in
+
http://11.hoolpy.dyn-o-saur.com/u6hgo8.html find ip address local network
+
http://7.host.is-a-geek.org/5fh8q.html transporting frozen food
+
http://5.dynos.gotdns.com/8nms9de.html around the world in 23 days
+
http://5.mywy.homeip.net/1mfl.html how to do illusion tricks
+
http://8.tests.dyndns.tv/b4hf8.html united states senate contact
+
http://10.neen.servegame.org/tyfs.html who are the gospels
+
http://9.fortor.dvrdns.org/izdis0a.html birthday parties metrowest
+
http://2.fortor.dvrdns.org/gxwb46.html history of mayonaise
+
http://6.host.is-a-geek.org/zk9m9.html heaviest woman in the world
+
http://7.tests.dyndns.tv/jv9grd.html today show recipes
+
http://11.webius.servebbs.com/s1ky0.html newton kansas newspapers
+
http://2.jonny.dnsalias.com/leaka.html igor vovchanchyn video
+
http://7.neen.servegame.org/8pyhy2.html how to change wiper blades
+
http://9.fortor.dvrdns.org/vjifbj8.html how to do a pap test
+
http://3.webius.servebbs.com/9x8i.html pcsxbox latest version
+
http://5.mywy.homeip.net/gyjxg.html womens final four
+
http://10.fortor.dvrdns.org/9qkb.html best in show dvd cover
+
http://9.wifin.shacknet.nu/izxtk.html where the sidewalk ends shel
+
http://3.fortor.dvrdns.org/bd4qjb8.html of africa showing all countries
+
http://2.webius.servebbs.com/urv5.html water cycle videos
+
http://3.jonny.dnsalias.com/42veou.html images of bridal bouquets
+
http://2.dynos.gotdns.com/dxwl8.html test broadband speeds
+
http://5.neen.servegame.org/my0c.html llonga apartments ibiza
+
http://8.fortor.dvrdns.org/shst5a2.html gulf coast movie times
+
http://6.wifin.shacknet.nu/0mlsq.html desktop games peter
+
http://10.host.is-a-geek.org/15a7.html to make frappichino
+
http://7.tests.dyndns.tv/xjv4g.html west virginia department education
+
http://1.fortor.dvrdns.org/it1yh0.html lamaison salad dressing
+
http://6.dynos.gotdns.com/oup27.html a walk in the woods test
+
http://11.jonny.dnsalias.com/he6ha.html number of baseball games per season
+
http://3.wifin.shacknet.nu/eqwat.html willie revillame and janelle
+
http://10.neen.servegame.org/nrc516.html how to make a boild
+
http://1.fortor.dvrdns.org/w20qy2n.html cowboy bebop wallpapers
+
http://4.webius.servebbs.com/qxh72.html alan jackson good time music
+
http://9.mywy.homeip.net/eszjc3.html how to be a millianare
+
http://4.hoolpy.dyn-o-saur.com/z78ve.html mutual fund assets under management
+
http://3.webius.servebbs.com/rgvpx5d.html employment services los angeles
+
http://3.mywy.homeip.net/uigd0wi.html flash slideshow 4.79
+
http://2.mywy.homeip.net/nyg7s0.html ballys las vegas shows
+
http://8.dynos.gotdns.com/mebj22h.html how to sell luxury real estate
+
http://5.neen.servegame.org/1p0bs9n.html liquid petroleum gas conversion
+
http://8.tests.dyndns.tv/717yp.html birthday princess party
+
http://1.mywy.homeip.net/du1i6y.html loadpicture function in
+
http://11.dynos.gotdns.com/me04iyh.html mlb08 the show official
+
http://2.hoolpy.dyn-o-saur.com/n8w9.html lake almanor real estate
+
http://7.dynos.gotdns.com/lzt18.html puppet master film
+
http://2.wifin.shacknet.nu/x9g4.html kemp town brighton uk
+
http://11.neen.servegame.org/swc3pk.html videos de amimales
+
http://9.webius.servebbs.com/202ld.html tropicana showroom atlantic city
+
http://2.jonny.dnsalias.com/61zyxmn.html gfi faxmaker sending
+
http://11.webius.servebbs.com/59wb.html why do you persecute
+
http://10.mywy.homeip.net/zhnnc92.html what not to do while pregnant
+
http://5.host.is-a-geek.org/lg2ow.html test braodband connection
+
http://2.jonny.dnsalias.com/6l2h.html windows xp home sp2 cd key
+
http://11.fortor.dvrdns.org/s582koi.html west virginia mountaineer clothing
+
http://7.hoolpy.dyn-o-saur.com/p9g6is.html holiday on king toronto
+
http://9.mywy.homeip.net/mdv7.html used mercedes benz parts
+
http://9.webius.servebbs.com/ryur9.html birthday wishes ecards
+
http://6.webius.servebbs.com/8i6y.html luton town fixtures
+
http://7.wifin.shacknet.nu/fnhjs1n.html department of motor vehicle form
+
http://2.dynos.gotdns.com/c3g6le.html chanderpaul six video
+
http://10.host.is-a-geek.org/hc7c.html stratton 12h802 parts
+
http://4.wifin.shacknet.nu/k0rt.html three days grace -i hate everything
+
http://1.webius.servebbs.com/ow5w7.html dog training careers
+
http://1.hoolpy.dyn-o-saur.com/8t8fz.html fantastic four 2 wallpaper
+
http://5.host.is-a-geek.org/ed5jx.html drug test questions
+
http://10.host.is-a-geek.org/99begm.html international caravan and motorhome show
+
http://4.fortor.dvrdns.org/736x51.html sopranos episode 34
+
http://8.jonny.dnsalias.com/sz4qh.html seattle and downtown
+
http://7.wifin.shacknet.nu/ik78.html where is brimstone
+
http://3.hoolpy.dyn-o-saur.com/5wcd2pb.html lyrics to hicktown by jason aldean
+
http://4.fortor.dvrdns.org/4snjw.html how to reach torna
+
http://9.jonny.dnsalias.com/pd5jk.html iwlwifi 3945 1 ucode
+
http://1.webius.servebbs.com/e63q.html pleasure i did you wrong video
+
http://2.jonny.dnsalias.com/ppvvikt.html sun newspaper on line
+
http://7.neen.servegame.org/z91by.html everyday alice walker
+
http://11.jonny.dnsalias.com/833s.html how to grow strawberries indoors
+
http://3.webius.servebbs.com/lptploi.html war of the worlds theme
+
http://3.hoolpy.dyn-o-saur.com/oydsju.html grandfather gifts for holiday
+
http://4.dynos.gotdns.com/oq4z.html paper hole punchers
+
http://2.jonny.dnsalias.com/2v6sx4j.html how to make fiberglass boxes
+
http://5.jonny.dnsalias.com/y93ozfn.html germanna community college home
+
http://7.fortor.dvrdns.org/34ueh.html neuropsychological assessment tests
+
http://11.host.is-a-geek.org/a6yh.html little codeck pack
+
http://5.webius.servebbs.com/399xw.html how to rebuild trust in relationships
+
http://8.mywy.homeip.net/70r8.html oakridge home furnishings
+
http://8.webius.servebbs.com/a5yvvro.html india vs south africa 3rd test day3
+
http://1.neen.servegame.org/lcyionw.html maritime academy castine maine
+
http://1.fortor.dvrdns.org/q4jt.html how to import outlook 2003
+
http://5.tests.dyndns.tv/rt63e28.html carol jo vecchie springfield
+
http://6.webius.servebbs.com/b3bh79u.html huxley and partners
+
http://5.hoolpy.dyn-o-saur.com/4n0e.html bible word search puzzle
+
http://10.jonny.dnsalias.com/60yml2.html codec to play divx
+
  
 
== '''Security''' ==
 
== '''Security''' ==

Revision as of 20:47, 30 March 2009

Configuration

What is the main configuration file for Fail2ban?

Fail2ban configuration process is rather simple. There is only one configuration file, where Fail2ban can be fully configured, this file is located at: /etc/fail2ban/fail2ban.conf

You are able to edit this file using any editor you want: vim, emacs, joe, ae...

Configuration file must be edited by root.

How can Fail2ban be configured?

This step is fully detailed at HOWTOs chapter

Can I exclude failed logins for selected users from resulting in a ban?

(I don't know, perhaps that's a feature request.)

Edit: Cause fail2ban didn't know anything of the username format logged in the specific file(s) (if usernames even get logged), it is only possible to exclude selected users in the regex of the service section.

Is there a way to have bans persist over restarts and log rotation?

Security

What do I have to consider when using Fail2ban?

Especially on systems which provide SSH/CGI/PHP services to unknown users, it is possible to block other users from ssh and probably other services. How would a user do so? The user could issue:

logger -p auth.warning -t 'sshd[123]' 'Illegal user user1 from 1.2.3.4'

Or the malicious user may write via PHP's openlog()/syslog() to syslog.

Solution #1: This security hazard can be handled via ownership/permissions of /dev/log, which allows logging to all the users by default. Just add a group log, add all daemons and root to that group and be happy.

What about log injection?

Fail2ban parses log files of other services and thus it can be vulnerable to log injection. Daniel B. Cid describes this kind of issues in Attacking Log analysis tools. I strongly suggest that you read this article. We will always try to provide safe configuration files. However, you can use fail2ban-regex to test your configuration files against forged log lines.

Troubleshooting

I have Postfix on my system but no "mail" command. How can I get e-mail notifications?

As of version 0.8.1, "mail" actions are deprecated. Please use the "sendmail" ones instead. E.g. sendmail-whois instead of mail-whois in your jail.[conf|local].

You probably have the sendmail command. Copy /etc/fail2ban/action.d/mail-whois.conf to /etc/fail2ban/action.d/mail-whois.local, edit this file and replace mail with sendmail. Here is an example:

actionban = echo -en "From:root <fail2ban>
            To: <dest>
            Subject: [Fail2Ban] <name>: banned <ip>
            Hi,\n
            The IP <ip> has just been banned by Fail2Ban after
            <failures> attempts against <name>.\n\n
            Here are more information about <ip>:\n
            `whois <ip>`\n
            Regards,\n
            Fail2Ban"|sendmail -t  

mail.conf can be modified too.

Why do my CVS users using SSH getting blocked?

If you are using the Eclipse CVS integration with SSH, then each access of the CVS results in a failed access before a valid one is done. As a consequence your CVS users get banned from time to time.

I get the error "Please check the format and your locale settings"

The error looks like this:

ERROR: time data did not match format: data=Mar 21 10:00:50 fmt=%b %d %H:%M:%S
ERROR: Please check the format and your locale settings.

This is a known bug. Since 0.6.1, Fail2ban uses your locale settings for date and time format. However, some daemons do not take care of locale and write their log messages using the POSIX standard. Please look at this bug for more details.

You can try to override the LANG variable:

# LANG=en_US /etc/init.d/fail2ban restart

You can get all the available locale with:

# locale -a

How do I increase verbosity?

In order to increase the verbosity of Fail2ban, use the command line option -vvv for fail2ban-client and fail2ban (only for 0.6.x). Set loglevel to 4 in /etc/fail2ban/fail2ban.conf (only for > 0.6.x).

Fail2ban is running but not banning SSH bruteforce

NB:This example is based on a Debian system, but can be easily done on any distro.

The package is well installed:

# dpkg -l |grep fail                                               
ii  fail2ban                      0.8.1-2                         bans IPs that 
cause multiple authentication

The service is running:

# /etc/init.d/fail2ban status                                      
Status of authentication failure monitor: fail2ban is running

SSH jail is set up and ready:

# fail2ban-client status                                           
Status                                                                          
|- Number of jail:      1                                                       
`- Jail list:           ssh

SSH bruteforce logs are identified by fail2ban:

# fail2ban-regex /var/log/auth.log /etc/fail2ban/filter.d/sshd.conf
....
Success, the total number of match is 30

So, check that all your logs are synchronized: all logs files (auth.log, syslog,..) must use the same time reference (if your server is not very busy, there will probably be an important difference between the output of [1]date command and the last event logged in syslog. You can force to generate a log in syslog using the logger command and check then with the output of date command)

# date                                                             
Wed Nov 28 13:49:02 CET 2007                                                    
# tail -2 /var/log/auth.log                                        
Nov 28 13:39:12 <SERVERNAME> sudo: pam_unix(sudo:session): session opened for user roo
t by <user>(uid=0)                                                              
Nov 28 13:39:12 <SERVERNAME> sudo: pam_unix(sudo:session): session closed for user roo
t

If time reference is not the same everywhere, then fail2ban won't ban any IP!