39

I can't seem to find a quick command to just view all the banned IP's on the server. Or is there a file I can just edit?

I'm guessing fail2ban is the one that inputs all the IP's to ban. Where do I adjust the settings for it?

I seem to be able to only login to my server remotely only if i disable ufw. I can't seem to find out how to unban myself. I don't even know why i was banned in the first place. Is there a log of some sort to view all the attempts made?

7
  • 5
    sudo iptables -L -n?
    – Seth
    Jun 24, 2014 at 18:36
  • there is so much output. what am i suppose to look for? i.imgur.com/zTTXJTE.png ... thanks .. i did a ufw allow <ip_address> and it still didnt work. i dont know where it says its banned. Jun 24, 2014 at 21:07
  • Also did a ufw status and and then disable ufw, did a iptables -F, then ufw enable. Still i can't access my server remotely. My ip clearly is shown in the status box as allow: i.imgur.com/f7JD2Ny.png Jun 24, 2014 at 21:13
  • have you open the ssh port before sshing the server ?
    – Qasim
    Jun 26, 2014 at 18:57
  • how do i check that? I can SSH in when the firewall is off. so isnt it working by default? Jun 26, 2014 at 19:11

3 Answers 3

48

short version:

list all currently blocked ips:

fail2ban-client status | grep "Jail list:" | sed "s/ //g" | awk '{split($2,a,",");for(i in a) system("fail2ban-client status " a[i])}' | grep "Status\|IP list"

unban an ip:

fail2ban-client set postfix-mail unbanip 111.222.333.444

long version:

if you are looking for the "official" way to do that, there is a command line client for fail2ban https://www.fail2ban.org/wiki/index.php/Commands :

~ # fail2ban-client status
Status
|- Number of jail:      8
`- Jail list:           roundcube, sshd, sogo, postfix-sasl, postfix-mail, dovecot, ssh, sshd-ddos

then you can run

~ # fail2ban-client status roundcube

Status for the jail: roundcube
|- filter
|  |- File list:        /var/log/mail.log
|  |- Currently failed: 0
|  `- Total failed:     12
`- action
   |- Currently banned: 1
   |  `- IP list:       111.222.333.444
   `- Total banned:     1

or you can use my command, which iterates over all existing jails:

fail2ban-client status | grep "Jail list:" | sed "s/ //g" | awk '{split($2,a,",");for(i in a) system("fail2ban-client status " a[i])}' | grep "Status\|IP list"

which outputs:

Status for the jail: roundcube
   |  `- IP list:
Status for the jail: sshd
   |  `- IP list:
Status for the jail: sogo
   |  `- IP list:
Status for the jail: postfix-sasl
   |  `- IP list:
Status for the jail: postfix-mail
   |  `- IP list:
Status for the jail: dovecot
   |  `- IP list:
Status for the jail: ssh
   |  `- IP list:
Status for the jail: sshd-ddos
   |  `- IP list:
2
  • Should be the accepted answer now.
    – Basj
    Apr 20, 2018 at 13:16
  • without awk: fail2ban-client status | grep "Jail list:" | sed "s/`- Jail list://" | sed "s/\s//g" | sed "s/,/\n/g" | xargs -L1 fail2ban-client status | less
    – Quamis
    May 28, 2019 at 12:52
27
+50

sudo iptables -L INPUT -v -n | less

This tells iptables to List all rules in the INPUT chain, providing verbose numeric output. We are piping through less so that we get it a page at a time.

4
  • 2
    Maybe something changed since 2014 but as things stand now, this answer is wrong since fail2ban doesn't put things in the INPUT chain. Jul 21, 2017 at 4:05
  • @billynoah Of course somethings changed. Nothing in life is static. For one, 12.04 is no longer under support. If you are still using it I recommend that you upgrade to 16.04 LTS which is supported until April 2021.
    – Elder Geek
    Jul 21, 2017 at 12:23
  • I'm not sure if you're referencing 12.04 because I said 2014? I was talking about the year of your answer. Jul 21, 2017 at 12:26
  • 1
    @billynoah I'm referencing 12.04 due the the fact that it's referenced in the question that this answer was provided for. You have my apologies for any confusion you may be experiencing. :-)
    – Elder Geek
    Jul 22, 2017 at 18:46
21

You can see all the previously banned IPs through /var/log/fail2ban.log

sudo zgrep 'Ban' /var/log/fail2ban.log*

Some bans are temporary though, so I'm not sure how to best cancel those out (my fail2ban logs are empty which makes this harder to test!). You could enter into a big accounting scheme with the awk command, but it's getting pretty dull.

Anyway, that's the way you want to do it if you're looking for a reason why you were banned.

The other way is to look at IP tables and see what's being dropped. Again, this has some problems because it shows default routes that get overridden but I'm blocking rules with a source of 0.0.0.0/0 and that seems to keep it clean enough for practical use:

sudo iptables -L -n | awk '$1=="DROP" && $4!="0.0.0.0/0"'

This won't explain why a ban happened though.

3
  • is fail2ban the main application that does the banning and not any other app? my server is just a basic ubuntu server so i never installed anything else into it. Jul 2, 2014 at 19:51
  • In that case, yes.
    – Oli
    Jul 2, 2014 at 20:06
  • 1
    Note that my current version writes NOTICE [snap-iptables] Ban 45.32.216.148 -- no ':' after the word Ban, but spaces before and after. Oct 22, 2016 at 3:00

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