directadmin anti brute force ipfw

[golfreeze]

http://help.directadmin.com/item.php?id=380

I wish to have a block_ip.sh so I can block IPs through DirectAdmin   
*** DirectAdmin technical support does not include firewalls, so any use of this guide will be at your own risk, and beyond the reach of our technical support ***

Read all text included with each step!


1) The first part of thie guide will outline how to setup the actual firewall for the block_ip.sh to use.  Note that we're not able to offer any support for this setup, so use it at your own risk.    Also, this file is written for a CentOS/Fedora type system and has not been tested on Debian or FreeBSD (it may work on Debian, not sure).
cd /etc/init.d
mv iptables iptables.backup
wget http://files.directadmin.com/services/all/iptables
chmod 755 iptables

*** Note that it opens ssh on port 22, so make sure you either change it manually, or have physical access to your server if you're running ssh on some other port.

You'll want to test this out to ensure it works for you:
/etc/init.d/iptables restart

to make sure you can still connect to everything ok.  If not, you may need to head to the datacenter to shut it off (partly why we don't offer support for firewalls)

2) The second step is to install the block_ip.sh so you can create a file that lists the IPs to be blocked.   A sample block_ip.sh can be found here.
To install this file, type:
cd /usr/local/directadmin/scripts/custom
wget http://files.directadmin.com/services/all/block_ip.sh
wget http://files.directadmin.com/services/all/show_blocked_ips.sh
wget http://files.directadmin.com/services/all/unblock_ip.sh
chmod 700 block_ip.sh show_blocked_ips.sh unblock_ip.sh

This should activate the button in DA at:
Admin Level -> Brute Force Monitor -> IP Info -> Block IP

This particular block_ip.sh script will check to ensure that the IP you're blocking does not already exist in the list.
It will also generate the output from "iptables -nL" which should show you everything that is current blocked in the list. (iptables -nL is also output in the event the IP is already blocked, so you can see your iptables list without doing anything)

3) Create the empty block list and exempt list files:
touch /root/blocked_ips.txt
touch /root/exempt_ips.txt




4) This last step is optional and should only be used after you've tested the above setup for a while to get comfortable that you're not going to block yourself.   The block_ip.sh is only used for an active "click" by the Admin, it does not automate blocking.  To automate blocking, install the following script:
cd /usr/local/directadmin/scripts/custom
wget http://files.directadmin.com/services/all/brute_force_notice_ip.sh
chmod 700 brute_force_notice_ip.sh




If you're running FreeBSD with ipfw, you'd skip steps 1, 2 and 3, and instead, add the following code to the file:
/usr/local/directadmin/scripts/custom/block_ip.sh

#!/bin/sh
echo "Blocking $ip with ipfw ...<br>";
ipfw add deny ip from $ip to any
exit $?

and don't forget to chmod the block_ip.sh to 755.

Update: Nov 8, 2012
A guide was written on the forum:
http://www.directadmin.com/forum/showthread.php?t=42202&page=1
which provides more options.

We've changed our 3 scripts above (step 2) to use the ipfw commands from the mentioned guide (with 'table 10'), but since they use the /root/blocked_ips.txt file, they also support the dateblocked feature, thus can be used for the auto-unblock option.