Shorewall

Shorewall is a highly flexible firewall. Its configuration can be found in /etc/shorewall.

Installation

• to install shorewall:

  sudo apt-get install shorewall
  

• define the interfaces in /etc/shorewall/interfaces:

  net eth0 detect routefilter,tcpflags
  

• define the zones in /etc/shorewall/zones:

  fw firewall
  net ipv4
  

• define the default policies in /etc/shorewall/policy:

  net all DROP
  fw all ACCEPT
  

• define the rules in /etc/shorewall/rules:

  #SECTION ALL
  #SECTION ESTABLISHED
  #SECTION RELATED
  SECTION NEW
  Invalid(DROP)   net             all
  DNS(ACCEPT)     $FW             net
  SSH(ACCEPT)     all             $FW
  Ping(ACCEPT)    net             $FW
  

• test the configuration:

  shorewall check
  

• apply the configuration:

  shorewall start
  

Start

sudo /etc/init.d/shorewall start

Stop

sudo /etc/init.d/shorewall stop

Disable

sed -i s/startup=1/startup=0/g /etc/default/shorewall

Enable

sed -i s/startup=0/startup=1/g /etc/default/shorewall

Responsible

Alexander Werner, Robert Einsle