freebsd-src/etc/rc.firewall
Sheldon Hearn f66e7afa28 Add to defaults/rc.conf a new function source_rc_confs which rc
scripts may use to source safely overrides in ${rc_conf_files}
files.

This protects users who insist on the bad practice of copying
/etc/defaults/rc.conf to /etc/rc.conf from a recursive loop
that exhausts available file descriptors.

Several people have expressed interest in breaking this function
out into its own shell script.  Anyone who wants to embark on
such an undertaking would do well to study the attributed PR.

PR:		17595
Reported by:	adrian
Submitted by:	Doug Barton <Doug@gorean.org>
2000-04-27 08:43:49 +00:00

237 lines
6.8 KiB
Plaintext

############
# Setup system for firewall service.
# $FreeBSD$
# Suck in the configuration variables.
if [ -r /etc/defaults/rc.conf ]; then
. /etc/defaults/rc.conf
source_rc_confs
elif [ -r /etc/rc.conf ]; then
. /etc/rc.conf
fi
############
# Define the firewall type in /etc/rc.conf. Valid values are:
# open - will allow anyone in
# client - will try to protect just this machine
# simple - will try to protect a whole network
# closed - totally disables IP services except via lo0 interface
# UNKNOWN - disables the loading of firewall rules.
# filename - will load the rules in the given filename (full path required)
#
# For ``client'' and ``simple'' the entries below should be customized
# appropriately.
############
#
# If you don't know enough about packet filtering, we suggest that you
# take time to read this book:
#
# Building Internet Firewalls
# Brent Chapman and Elizabeth Zwicky
#
# O'Reilly & Associates, Inc
# ISBN 1-56592-124-0
# http://www.ora.com/
#
# For a more advanced treatment of Internet Security read:
#
# Firewalls & Internet Security
# Repelling the wily hacker
# William R. Cheswick, Steven M. Bellowin
#
# Addison-Wesley
# ISBN 0-201-6337-4
# http://www.awl.com/
#
if [ -n "${1}" ]; then
firewall_type="${1}"
fi
############
# Set quiet mode if requested
#
case ${firewall_quiet} in
[Yy][Ee][Ss])
fwcmd="/sbin/ipfw -q"
;;
*)
fwcmd="/sbin/ipfw"
;;
esac
############
# Flush out the list before we begin.
#
${fwcmd} -f flush
############
# These rules are required for using natd. All packets are passed to
# natd before they encounter your remaining rules. The firewall rules
# will then be run again on each packet after translation by natd,
# minus any divert rules (see natd(8)).
#
case ${natd_enable} in
[Yy][Ee][Ss])
if [ -n "${natd_interface}" ]; then
${fwcmd} add divert natd all from any to any via ${natd_interface}
fi
;;
esac
############
# If you just configured ipfw in the kernel as a tool to solve network
# problems or you just want to disallow some particular kinds of traffic
# then you will want to change the default policy to open. You can also
# do this as your only action by setting the firewall_type to ``open''.
#
# ${fwcmd} add 65000 pass all from any to any
############
# Only in rare cases do you want to change these rules
#
${fwcmd} add 100 pass all from any to any via lo0
${fwcmd} add 200 deny all from any to 127.0.0.0/8
# If you're using 'options BRIDGE', uncomment the following line to pass ARP
#${fwcmd} add 300 pass udp from 0.0.0.0 2054 to 0.0.0.0
# Prototype setups.
#
case ${firewall_type} in
[Oo][Pp][Ee][Nn])
${fwcmd} add 65000 pass all from any to any
;;
[Cc][Ll][Ii][Ee][Nn][Tt])
############
# This is a prototype setup that will protect your system somewhat
# against people from outside your own network.
############
# set these to your network and netmask and ip
net="192.0.2.0"
mask="255.255.255.0"
ip="192.0.2.1"
# Allow any traffic to or from my own net.
${fwcmd} add pass all from ${ip} to ${net}:${mask}
${fwcmd} add pass all from ${net}:${mask} to ${ip}
# Allow TCP through if setup succeeded
${fwcmd} add pass tcp from any to any established
# Allow IP fragments to pass through
${fwcmd} add pass all from any to any frag
# Allow setup of incoming email
${fwcmd} add pass tcp from any to ${ip} 25 setup
# Allow setup of outgoing TCP connections only
${fwcmd} add pass tcp from ${ip} to any setup
# Disallow setup of all other TCP connections
${fwcmd} add deny tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from any 53 to ${ip}
${fwcmd} add pass udp from ${ip} to any 53
# Allow NTP queries out in the world
${fwcmd} add pass udp from any 123 to ${ip}
${fwcmd} add pass udp from ${ip} to any 123
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
# config file.
;;
[Ss][Ii][Mm][Pp][Ll][Ee])
############
# This is a prototype setup for a simple firewall. Configure this
# machine as a named server and ntp server, and point all the machines
# on the inside at this machine for those services.
############
# set these to your outside interface network and netmask and ip
oif="ed0"
onet="192.0.2.0"
omask="255.255.255.240"
oip="192.0.2.1"
# set these to your inside interface network and netmask and ip
iif="ed1"
inet="192.0.2.16"
imask="255.255.255.240"
iip="192.0.2.17"
# Stop spoofing
${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif}
${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif}
# Stop RFC1918 nets on the outside interface
${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif}
${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif}
${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif}
${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif}
${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif}
${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif}
# Stop draft-manning-dsua-01.txt nets on the outside interface
${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif}
${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif}
${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif}
${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif}
${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif}
${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif}
${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif}
${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif}
${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif}
${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif}
# Allow TCP through if setup succeeded
${fwcmd} add pass tcp from any to any established
# Allow IP fragments to pass through
${fwcmd} add pass all from any to any frag
# Allow setup of incoming email
${fwcmd} add pass tcp from any to ${oip} 25 setup
# Allow access to our DNS
${fwcmd} add pass tcp from any to ${oip} 53 setup
${fwcmd} add pass udp from any to ${oip} 53
${fwcmd} add pass udp from ${oip} 53 to any
# Allow access to our WWW
${fwcmd} add pass tcp from any to ${oip} 80 setup
# Reject&Log all setup of incoming connections from the outside
${fwcmd} add deny log tcp from any to any in via ${oif} setup
# Allow setup of any other TCP connection
${fwcmd} add pass tcp from any to any setup
# Allow DNS queries out in the world
${fwcmd} add pass udp from any 53 to ${oip}
${fwcmd} add pass udp from ${oip} to any 53
# Allow NTP queries out in the world
${fwcmd} add pass udp from any 123 to ${oip}
${fwcmd} add pass udp from ${oip} to any 123
# Everything else is denied by default, unless the
# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
# config file.
;;
[Uu][Nn][Kk][Nn][Oo][Ww][Nn])
;;
*)
if [ -r "${firewall_type}" ]; then
${fwcmd} ${firewall_flags} ${firewall_type}
fi
;;
esac