iptables
# apt-get install hubzero-mw-firewall
HUBzero requires the use of iptables to route network connections between application sessions and the external network. The scripts controlling this can also be used to manage basic firewall operations for the site. If you use manage iptables with other tools you will have to make sure the rules in these scripts are maintained. /etc/mw/firewall_on and /etc/mw/firewall_off turn the HUBzero firewall on and off respectively. A link from /etc/rc.boot/firewall_on to /etc/mw/firewall_on causes the script to run at startup (this link was created for you).
The basic scripts installed here block all access to the host except for those ports required by HUBzero (http,https,http-alt,ldap,ssh.smtp,mysql,submit,etc).