agnostic-firewall

Manage your Netfilter rules whitout worring about IPv4 IPv6 protocols.

The base idea: on dual-stack (IPv4/IPv6), most of the Netfilter rules are identical.

The goal: factorize as much as possible the Netfilter rules.

Installation:

git clone https://github.com/lspagnol/agnostic-firewall
cd agnostic-firewall
sh install.sh

Configuration:

/etc/firewall/firewall.cf

• Main configuration file.
• The rulesets filenames can be changed by editing the RULES variable.
• IPv4 or IPv6 firewall can be disabled by uncomment V4_DISABLE or V6_DISABLE.

/etc/firewall/Base.rules

• Basic common rules: loopback, established, routing and IPv6 neighbor, various ICMP, …

/etc/firewall/Admin.rules

• Allow connexions from your administrative hosts or networks.

/etc/firewall/Services.rules

• Grant only necessary access from the world to your server,
• give it only necessary access to the world (such as LDAP, SQL, …),

Syntax of rules:

• Just replace iptables/ip6tables with ipt.
• The script will try to know if rules apply to IPv4, IPv6 or both:
  • check type of IP addresses,
  • resolve V4/V6 addresses for host/fqdn based rule.
• Declaration can be explicit: use ipt4 or ipt6 instead of ipt.

/etc/firewall/{pre|post}-{start|stop|save}

• Theses hook scripts, as defined in /etc/firewall/firewall.cf are included if available:
  • pre-save.sh, pre-save_V4.sh, pre-save_V6.sh
  • post-save.sh, post-save_V4.sh, post-save_V6.sh
  • pre-start.sh, pre-start_V4.sh, pre-start_V6.sh
  • post-start.sh, post-start_V4.sh, post-start_V6.sh
  • pre-stop.sh, pre-stop_V4.sh, pre-stop_V6.sh
  • post-stop.sh, post-stop_V4.sh, post-stop_V6.sh
• You can use Bash syntax.
• Global variables of main script are available.
• It’s recommended to use ipt, ipt4 or ipt6 instead of iptables or ip6tables.

  Examples (use Agnostic-Firewall with SimpleBan):

  • post-start.sh:

    # SimpleBan
    if [ -x /usr/local/sbin/sban ] ; then
    ipt -N BANNED
    ipt -I INPUT -j BANNED
    ipt -I OUTPUT -j BANNED
    ipt -I FORWARD -j BANNED
    /usr/local/sbin/sban start
    fi

  • pre-stop.sh:

    # SimpleBan
    if [ -x /usr/local/sbin/sban ] ; then
    /usr/local/sbin/sban stop
    fi

  • post-save.sh is just a symlink:

    ln -s /etc/firewall/post-start.sh /etc/firewall/post-save.sh

Usage:

Rules management:

• Edit the ruleset of your services: nano /etc/firewall/Services.rules
• Compile your rules: firewall compile
• Try your rules (with automatic flush of rules for nuts like me …) : firewall try
• It’s okay ? … then apply your rules: firewall apply
• Save the Netfilter rules (they will be applied at boot time): firewall save
  • The compiled IPv4 rules are stored in /etc/firewall/firewall_V4.sv
  • The compiled IPv6 rules are stored in /etc/firewall/firewall_V6.sv
• If you have done some minor changes on your rules or you whish to update them (FQDN resolution): just do firewall update

Firewall management:

• Start firewall: firewall start or service firewall start
• Stop firewall (flush rules and set policy to accept): firewall stop or service firewall stop