1#!/bin/sh 2# Copyright (c) 1996 Poul-Henning Kamp 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms, with or without 6# modification, are permitted provided that the following conditions 7# are met: 8# 1. Redistributions of source code must retain the above copyright 9# notice, this list of conditions and the following disclaimer. 10# 2. Redistributions in binary form must reproduce the above copyright 11# notice, this list of conditions and the following disclaimer in the 12# documentation and/or other materials provided with the distribution. 13# 14# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24# SUCH DAMAGE. 25# 26# $FreeBSD: src/etc/rc.firewall,v 1.30.2.16 2003/02/10 05:45:06 trhodes Exp $ 27# $DragonFly: src/etc/rc.firewall,v 1.2 2003/06/17 04:24:45 dillon Exp $ 28# 29 30# 31# Setup system for firewall service. 32# 33 34# Suck in the configuration variables. 35if [ -z "${source_rc_confs_defined}" ]; then 36 if [ -r /etc/defaults/rc.conf ]; then 37 . /etc/defaults/rc.conf 38 source_rc_confs 39 elif [ -r /etc/rc.conf ]; then 40 . /etc/rc.conf 41 fi 42fi 43 44############ 45# Define the firewall type in /etc/rc.conf. Valid values are: 46# open - will allow anyone in 47# client - will try to protect just this machine 48# simple - will try to protect a whole network 49# closed - totally disables IP services except via lo0 interface 50# UNKNOWN - disables the loading of firewall rules. 51# filename - will load the rules in the given filename (full path required) 52# 53# For ``client'' and ``simple'' the entries below should be customized 54# appropriately. 55 56############ 57# 58# If you don't know enough about packet filtering, we suggest that you 59# take time to read this book: 60# 61# Building Internet Firewalls, 2nd Edition 62# Brent Chapman and Elizabeth Zwicky 63# 64# O'Reilly & Associates, Inc 65# ISBN 1-56592-871-7 66# http://www.ora.com/ 67# http://www.oreilly.com/catalog/fire2/ 68# 69# For a more advanced treatment of Internet Security read: 70# 71# Firewalls & Internet Security 72# Repelling the wily hacker 73# William R. Cheswick, Steven M. Bellowin 74# 75# Addison-Wesley 76# ISBN 0-201-63357-4 77# http://www.awl.com/ 78# http://www.awlonline.com/product/0%2C2627%2C0201633574%2C00.html 79# 80 81setup_loopback () { 82 ############ 83 # Only in rare cases do you want to change these rules 84 # 85 ${fwcmd} add 100 pass all from any to any via lo0 86 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 87 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 88} 89 90if [ -n "${1}" ]; then 91 firewall_type="${1}" 92fi 93 94############ 95# Set quiet mode if requested 96# 97case ${firewall_quiet} in 98[Yy][Ee][Ss]) 99 fwcmd="/sbin/ipfw -q" 100 ;; 101*) 102 fwcmd="/sbin/ipfw" 103 ;; 104esac 105 106############ 107# Flush out the list before we begin. 108# 109${fwcmd} -f flush 110 111############ 112# Network Address Translation. All packets are passed to natd(8) 113# before they encounter your remaining rules. The firewall rules 114# will then be run again on each packet after translation by natd 115# starting at the rule number following the divert rule. 116# 117# For ``simple'' firewall type the divert rule should be put to a 118# different place to not interfere with address-checking rules. 119# 120case ${firewall_type} in 121[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 122 case ${natd_enable} in 123 [Yy][Ee][Ss]) 124 if [ -n "${natd_interface}" ]; then 125 ${fwcmd} add 50 divert natd all from any to any via ${natd_interface} 126 fi 127 ;; 128 esac 129esac 130 131############ 132# If you just configured ipfw in the kernel as a tool to solve network 133# problems or you just want to disallow some particular kinds of traffic 134# then you will want to change the default policy to open. You can also 135# do this as your only action by setting the firewall_type to ``open''. 136# 137# ${fwcmd} add 65000 pass all from any to any 138 139 140# Prototype setups. 141# 142case ${firewall_type} in 143[Oo][Pp][Ee][Nn]) 144 setup_loopback 145 ${fwcmd} add 65000 pass all from any to any 146 ;; 147 148[Cc][Ll][Ii][Ee][Nn][Tt]) 149 ############ 150 # This is a prototype setup that will protect your system somewhat 151 # against people from outside your own network. 152 ############ 153 154 # set these to your network and netmask and ip 155 net="192.0.2.0" 156 mask="255.255.255.0" 157 ip="192.0.2.1" 158 159 setup_loopback 160 161 # Allow any traffic to or from my own net. 162 ${fwcmd} add pass all from ${ip} to ${net}:${mask} 163 ${fwcmd} add pass all from ${net}:${mask} to ${ip} 164 165 # Allow TCP through if setup succeeded 166 ${fwcmd} add pass tcp from any to any established 167 168 # Allow IP fragments to pass through 169 ${fwcmd} add pass all from any to any frag 170 171 # Allow setup of incoming email 172 ${fwcmd} add pass tcp from any to ${ip} 25 setup 173 174 # Allow setup of outgoing TCP connections only 175 ${fwcmd} add pass tcp from ${ip} to any setup 176 177 # Disallow setup of all other TCP connections 178 ${fwcmd} add deny tcp from any to any setup 179 180 # Allow DNS queries out in the world 181 ${fwcmd} add pass udp from ${ip} to any 53 keep-state 182 183 # Allow NTP queries out in the world 184 ${fwcmd} add pass udp from ${ip} to any 123 keep-state 185 186 # Everything else is denied by default, unless the 187 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 188 # config file. 189 ;; 190 191[Ss][Ii][Mm][Pp][Ll][Ee]) 192 ############ 193 # This is a prototype setup for a simple firewall. Configure this 194 # machine as a named server and ntp server, and point all the machines 195 # on the inside at this machine for those services. 196 ############ 197 198 # set these to your outside interface network and netmask and ip 199 oif="ed0" 200 onet="192.0.2.0" 201 omask="255.255.255.240" 202 oip="192.0.2.1" 203 204 # set these to your inside interface network and netmask and ip 205 iif="ed1" 206 inet="192.0.2.16" 207 imask="255.255.255.240" 208 iip="192.0.2.17" 209 210 setup_loopback 211 212 # Stop spoofing 213 ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif} 214 ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif} 215 216 # Stop RFC1918 nets on the outside interface 217 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 218 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 219 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 220 221 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 222 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 223 # on the outside interface 224 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 225 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 226 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 227 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 228 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 229 230 # Network Address Translation. This rule is placed here deliberately 231 # so that it does not interfere with the surrounding address-checking 232 # rules. If for example one of your internal LAN machines had its IP 233 # address set to 192.0.2.1 then an incoming packet for it after being 234 # translated by natd(8) would match the `deny' rule above. Similarly 235 # an outgoing packet originated from it before being translated would 236 # match the `deny' rule below. 237 case ${natd_enable} in 238 [Yy][Ee][Ss]) 239 if [ -n "${natd_interface}" ]; then 240 ${fwcmd} add divert natd all from any to any via ${natd_interface} 241 fi 242 ;; 243 esac 244 245 # Stop RFC1918 nets on the outside interface 246 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 247 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 248 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 249 250 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 251 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 252 # on the outside interface 253 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 254 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 255 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 256 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 257 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 258 259 # Allow TCP through if setup succeeded 260 ${fwcmd} add pass tcp from any to any established 261 262 # Allow IP fragments to pass through 263 ${fwcmd} add pass all from any to any frag 264 265 # Allow setup of incoming email 266 ${fwcmd} add pass tcp from any to ${oip} 25 setup 267 268 # Allow access to our DNS 269 ${fwcmd} add pass tcp from any to ${oip} 53 setup 270 ${fwcmd} add pass udp from any to ${oip} 53 271 ${fwcmd} add pass udp from ${oip} 53 to any 272 273 # Allow access to our WWW 274 ${fwcmd} add pass tcp from any to ${oip} 80 setup 275 276 # Reject&Log all setup of incoming connections from the outside 277 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 278 279 # Allow setup of any other TCP connection 280 ${fwcmd} add pass tcp from any to any setup 281 282 # Allow DNS queries out in the world 283 ${fwcmd} add pass udp from ${oip} to any 53 keep-state 284 285 # Allow NTP queries out in the world 286 ${fwcmd} add pass udp from ${oip} to any 123 keep-state 287 288 # Everything else is denied by default, unless the 289 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 290 # config file. 291 ;; 292 293[Cc][Ll][Oo][Ss][Ee][Dd]) 294 setup_loopback 295 ;; 296[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 297 ;; 298*) 299 if [ -r "${firewall_type}" ]; then 300 ${fwcmd} ${firewall_flags} ${firewall_type} 301 fi 302 ;; 303esac 304