Block IP addresses

Install

Install Firestarter GUI for iptables:

• https://help.ubuntu.com/community/IptablesHowTo

See also: Configure iptables Firewall

Fix syslog error at startup

• https://bugs.launchpad.net/ubuntu/+source/firestarter/+bug/776361

sudo gedit /etc/rsyslog.d/99-fixlog.conf

*.=info;*.=notice;*.=warn;\
        auth,authpriv.none;\
        cron,daemon.none;\
        mail,news.none -/var/log/messages

sudo service rsyslog restart

Enable block rule

To block 123.11.112.1 with iptables:

iptables -I INPUT -s 123.11.112.1 -j DROP

To enable this functionality in firestarter edit this file:

sudo gedit /etc/firestarter/user-post

Add the following line to the /etc/firestarter/user-post file:

$IPT -I INPUT -s 123.11.112.1 -j DROP

Restart service:

sudo service firestarter restart

iptables settings

List iptables settings:

sudo iptables -vnL

Clear all iptables settings

sudo -i

IPTABLES="$(which iptables)"

# RESET DEFAULT POLICIES
$IPTABLES -P INPUT ACCEPT
$IPTABLES -P FORWARD ACCEPT
$IPTABLES -P OUTPUT ACCEPT
$IPTABLES -t nat -P PREROUTING ACCEPT
$IPTABLES -t nat -P POSTROUTING ACCEPT
$IPTABLES -t nat -P OUTPUT ACCEPT
$IPTABLES -t mangle -P PREROUTING ACCEPT
$IPTABLES -t mangle -P OUTPUT ACCEPT

# FLUSH ALL RULES, ERASE NON-DEFAULT CHAINS
$IPTABLES -F
$IPTABLES -X
$IPTABLES -t nat -F
$IPTABLES -t nat -X
$IPTABLES -t mangle -F
$IPTABLES -t mangle -X

exit