rc.firewall revision 91019
1# Copyright (c) 1996 Poul-Henning Kamp 2# All rights reserved. 3# 4# Redistribution and use in source and binary forms, with or without 5# modification, are permitted provided that the following conditions 6# are met: 7# 1. Redistributions of source code must retain the above copyright 8# notice, this list of conditions and the following disclaimer. 9# 2. Redistributions in binary form must reproduce the above copyright 10# notice, this list of conditions and the following disclaimer in the 11# documentation and/or other materials provided with the distribution. 12# 13# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16# ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23# SUCH DAMAGE. 24# 25# $FreeBSD: head/etc/rc.firewall 91019 2002-02-21 13:14:19Z cjc $ 26# 27 28# 29# Setup system for firewall service. 30# 31 32# Suck in the configuration variables. 33if [ -z "${source_rc_confs_defined}" ]; then 34 if [ -r /etc/defaults/rc.conf ]; then 35 . /etc/defaults/rc.conf 36 source_rc_confs 37 elif [ -r /etc/rc.conf ]; then 38 . /etc/rc.conf 39 fi 40fi 41 42############ 43# Define the firewall type in /etc/rc.conf. Valid values are: 44# open - will allow anyone in 45# client - will try to protect just this machine 46# simple - will try to protect a whole network 47# closed - totally disables IP services except via lo0 interface 48# UNKNOWN - disables the loading of firewall rules. 49# filename - will load the rules in the given filename (full path required) 50# 51# For ``client'' and ``simple'' the entries below should be customized 52# appropriately. 53 54############ 55# 56# If you don't know enough about packet filtering, we suggest that you 57# take time to read this book: 58# 59# Building Internet Firewalls, 2nd Edition 60# Brent Chapman and Elizabeth Zwicky 61# 62# O'Reilly & Associates, Inc 63# ISBN 1-56592-871-7 64# http://www.ora.com/ 65# http://www.oreilly.com/catalog/fire2/ 66# 67# For a more advanced treatment of Internet Security read: 68# 69# Firewalls & Internet Security 70# Repelling the wily hacker 71# William R. Cheswick, Steven M. Bellowin 72# 73# Addison-Wesley 74# ISBN 0-201-63357-4 75# http://www.awl.com/ 76# http://www.awlonline.com/product/0%2C2627%2C0201633574%2C00.html 77# 78 79setup_loopback () { 80 ############ 81 # Only in rare cases do you want to change these rules 82 # 83 ${fwcmd} add 100 pass all from any to any via lo0 84 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 85 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 86} 87 88if [ -n "${1}" ]; then 89 firewall_type="${1}" 90fi 91 92############ 93# Set quiet mode if requested 94# 95case ${firewall_quiet} in 96[Yy][Ee][Ss]) 97 fwcmd="/sbin/ipfw -q" 98 ;; 99*) 100 fwcmd="/sbin/ipfw" 101 ;; 102esac 103 104############ 105# Flush out the list before we begin. 106# 107${fwcmd} -f flush 108 109############ 110# Network Address Translation. All packets are passed to natd(8) 111# before they encounter your remaining rules. The firewall rules 112# will then be run again on each packet after translation by natd 113# starting at the rule number following the divert rule. 114# 115# For ``simple'' firewall type the divert rule should be put to a 116# different place to not interfere with address-checking rules. 117# 118case ${firewall_type} in 119[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 120 case ${natd_enable} in 121 [Yy][Ee][Ss]) 122 if [ -n "${natd_interface}" ]; then 123 ${fwcmd} add 50 divert natd all from any to any via ${natd_interface} 124 fi 125 ;; 126 esac 127esac 128 129############ 130# If you just configured ipfw in the kernel as a tool to solve network 131# problems or you just want to disallow some particular kinds of traffic 132# then you will want to change the default policy to open. You can also 133# do this as your only action by setting the firewall_type to ``open''. 134# 135# ${fwcmd} add 65000 pass all from any to any 136 137 138# Prototype setups. 139# 140case ${firewall_type} in 141[Oo][Pp][Ee][Nn]) 142 setup_loopback 143 ${fwcmd} add 65000 pass all from any to any 144 ;; 145 146[Cc][Ll][Ii][Ee][Nn][Tt]) 147 ############ 148 # This is a prototype setup that will protect your system somewhat 149 # against people from outside your own network. 150 ############ 151 152 # set these to your network and netmask and ip 153 net="192.0.2.0" 154 mask="255.255.255.0" 155 ip="192.0.2.1" 156 157 setup_loopback 158 159 # Allow any traffic to or from my own net. 160 ${fwcmd} add pass all from ${ip} to ${net}:${mask} 161 ${fwcmd} add pass all from ${net}:${mask} to ${ip} 162 163 # Allow TCP through if setup succeeded 164 ${fwcmd} add pass tcp from any to any established 165 166 # Allow IP fragments to pass through 167 ${fwcmd} add pass all from any to any frag 168 169 # Allow setup of incoming email 170 ${fwcmd} add pass tcp from any to ${ip} 25 setup 171 172 # Allow setup of outgoing TCP connections only 173 ${fwcmd} add pass tcp from ${ip} to any setup 174 175 # Disallow setup of all other TCP connections 176 ${fwcmd} add deny tcp from any to any setup 177 178 # Allow DNS queries out in the world 179 ${fwcmd} add pass udp from ${ip} to any 53 keep-state 180 181 # Allow NTP queries out in the world 182 ${fwcmd} add pass udp from ${ip} to any 123 keep-state 183 184 # Everything else is denied by default, unless the 185 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 186 # config file. 187 ;; 188 189[Ss][Ii][Mm][Pp][Ll][Ee]) 190 ############ 191 # This is a prototype setup for a simple firewall. Configure this 192 # machine as a named server and ntp server, and point all the machines 193 # on the inside at this machine for those services. 194 ############ 195 196 # set these to your outside interface network and netmask and ip 197 oif="ed0" 198 onet="192.0.2.0" 199 omask="255.255.255.240" 200 oip="192.0.2.1" 201 202 # set these to your inside interface network and netmask and ip 203 iif="ed1" 204 inet="192.0.2.16" 205 imask="255.255.255.240" 206 iip="192.0.2.17" 207 208 setup_loopback 209 210 # Stop spoofing 211 ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif} 212 ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif} 213 214 # Stop RFC1918 nets on the outside interface 215 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 216 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 217 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 218 219 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 220 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 221 # on the outside interface 222 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 223 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 224 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 225 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 226 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 227 228 # Network Address Translation. This rule is placed here deliberately 229 # so that it does not interfere with the surrounding address-checking 230 # rules. If for example one of your internal LAN machines had its IP 231 # address set to 192.0.2.1 then an incoming packet for it after being 232 # translated by natd(8) would match the `deny' rule above. Similarly 233 # an outgoing packet originated from it before being translated would 234 # match the `deny' rule below. 235 case ${natd_enable} in 236 [Yy][Ee][Ss]) 237 if [ -n "${natd_interface}" ]; then 238 ${fwcmd} add divert natd all from any to any via ${natd_interface} 239 fi 240 ;; 241 esac 242 243 # Stop RFC1918 nets on the outside interface 244 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 245 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 246 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 247 248 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 249 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 250 # on the outside interface 251 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 252 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 253 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 254 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 255 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 256 257 # Allow TCP through if setup succeeded 258 ${fwcmd} add pass tcp from any to any established 259 260 # Allow IP fragments to pass through 261 ${fwcmd} add pass all from any to any frag 262 263 # Allow setup of incoming email 264 ${fwcmd} add pass tcp from any to ${oip} 25 setup 265 266 # Allow access to our DNS 267 ${fwcmd} add pass tcp from any to ${oip} 53 setup 268 ${fwcmd} add pass udp from any to ${oip} 53 269 ${fwcmd} add pass udp from ${oip} 53 to any 270 271 # Allow access to our WWW 272 ${fwcmd} add pass tcp from any to ${oip} 80 setup 273 274 # Reject&Log all setup of incoming connections from the outside 275 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 276 277 # Allow setup of any other TCP connection 278 ${fwcmd} add pass tcp from any to any setup 279 280 # Allow DNS queries out in the world 281 ${fwcmd} add pass udp from ${oip} to any 53 keep-state 282 283 # Allow NTP queries out in the world 284 ${fwcmd} add pass udp from ${oip} to any 123 keep-state 285 286 # Everything else is denied by default, unless the 287 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 288 # config file. 289 ;; 290 291[Cc][Ll][Oo][Ss][Ee][Dd]) 292 setup_loopback 293 ;; 294[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 295 ;; 296*) 297 if [ -r "${firewall_type}" ]; then 298 ${fwcmd} ${firewall_flags} ${firewall_type} 299 fi 300 ;; 301esac 302