rc.firewall revision 121881
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: head/etc/rc.firewall 121881 2003-11-02 07:31:44Z ru $ 27# 28 29# 30# Setup system for firewall service. 31# 32 33# Suck in the configuration variables. 34if [ -z "${source_rc_confs_defined}" ]; then 35 if [ -r /etc/defaults/rc.conf ]; then 36 . /etc/defaults/rc.conf 37 source_rc_confs 38 elif [ -r /etc/rc.conf ]; then 39 . /etc/rc.conf 40 fi 41fi 42 43############ 44# Define the firewall type in /etc/rc.conf. Valid values are: 45# open - will allow anyone in 46# client - will try to protect just this machine 47# simple - will try to protect a whole network 48# closed - totally disables IP services except via lo0 interface 49# UNKNOWN - disables the loading of firewall rules. 50# filename - will load the rules in the given filename (full path required) 51# 52# For ``client'' and ``simple'' the entries below should be customized 53# appropriately. 54 55############ 56# 57# If you don't know enough about packet filtering, we suggest that you 58# take time to read this book: 59# 60# Building Internet Firewalls, 2nd Edition 61# Brent Chapman and Elizabeth Zwicky 62# 63# O'Reilly & Associates, Inc 64# ISBN 1-56592-871-7 65# http://www.ora.com/ 66# http://www.oreilly.com/catalog/fire2/ 67# 68# For a more advanced treatment of Internet Security read: 69# 70# Firewalls & Internet Security 71# Repelling the wily hacker 72# William R. Cheswick, Steven M. Bellowin 73# 74# Addison-Wesley 75# ISBN 0-201-63357-4 76# http://www.awl.com/ 77# http://www.awlonline.com/product/0%2C2627%2C0201633574%2C00.html 78# 79 80setup_loopback () { 81 ############ 82 # Only in rare cases do you want to change these rules 83 # 84 ${fwcmd} add 100 pass all from any to any via lo0 85 ${fwcmd} add 200 deny all from any to 127.0.0.0/8 86 ${fwcmd} add 300 deny ip from 127.0.0.0/8 to any 87} 88 89if [ -n "${1}" ]; then 90 firewall_type="${1}" 91fi 92 93############ 94# Set quiet mode if requested 95# 96case ${firewall_quiet} in 97[Yy][Ee][Ss]) 98 fwcmd="/sbin/ipfw -q" 99 ;; 100*) 101 fwcmd="/sbin/ipfw" 102 ;; 103esac 104 105############ 106# Flush out the list before we begin. 107# 108${fwcmd} -f flush 109 110############ 111# Network Address Translation. All packets are passed to natd(8) 112# before they encounter your remaining rules. The firewall rules 113# will then be run again on each packet after translation by natd 114# starting at the rule number following the divert rule. 115# 116# For ``simple'' firewall type the divert rule should be put to a 117# different place to not interfere with address-checking rules. 118# 119case ${firewall_type} in 120[Oo][Pp][Ee][Nn]|[Cc][Ll][Ii][Ee][Nn][Tt]) 121 case ${natd_enable} in 122 [Yy][Ee][Ss]) 123 if [ -n "${natd_interface}" ]; then 124 ${fwcmd} add 50 divert natd all from any to any via ${natd_interface} 125 fi 126 ;; 127 esac 128esac 129 130############ 131# If you just configured ipfw in the kernel as a tool to solve network 132# problems or you just want to disallow some particular kinds of traffic 133# then you will want to change the default policy to open. You can also 134# do this as your only action by setting the firewall_type to ``open''. 135# 136# ${fwcmd} add 65000 pass all from any to any 137 138 139# Prototype setups. 140# 141case ${firewall_type} in 142[Oo][Pp][Ee][Nn]) 143 setup_loopback 144 ${fwcmd} add 65000 pass all from any to any 145 ;; 146 147[Cc][Ll][Ii][Ee][Nn][Tt]) 148 ############ 149 # This is a prototype setup that will protect your system somewhat 150 # against people from outside your own network. 151 ############ 152 153 # set these to your network and netmask and ip 154 net="192.0.2.0" 155 mask="255.255.255.0" 156 ip="192.0.2.1" 157 158 setup_loopback 159 160 # Allow any traffic to or from my own net. 161 ${fwcmd} add pass all from ${ip} to ${net}:${mask} 162 ${fwcmd} add pass all from ${net}:${mask} to ${ip} 163 164 # Allow TCP through if setup succeeded 165 ${fwcmd} add pass tcp from any to any established 166 167 # Allow IP fragments to pass through 168 ${fwcmd} add pass all from any to any frag 169 170 # Allow setup of incoming email 171 ${fwcmd} add pass tcp from any to ${ip} 25 setup 172 173 # Allow setup of outgoing TCP connections only 174 ${fwcmd} add pass tcp from ${ip} to any setup 175 176 # Disallow setup of all other TCP connections 177 ${fwcmd} add deny tcp from any to any setup 178 179 # Allow DNS queries out in the world 180 ${fwcmd} add pass udp from ${ip} to any 53 keep-state 181 182 # Allow NTP queries out in the world 183 ${fwcmd} add pass udp from ${ip} to any 123 keep-state 184 185 # Everything else is denied by default, unless the 186 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 187 # config file. 188 ;; 189 190[Ss][Ii][Mm][Pp][Ll][Ee]) 191 ############ 192 # This is a prototype setup for a simple firewall. Configure this 193 # machine as a DNS and NTP server, and point all the machines 194 # on the inside at this machine for those services. 195 ############ 196 197 # set these to your outside interface network and netmask and ip 198 oif="ed0" 199 onet="192.0.2.0" 200 omask="255.255.255.240" 201 oip="192.0.2.1" 202 203 # set these to your inside interface network and netmask and ip 204 iif="ed1" 205 inet="192.0.2.16" 206 imask="255.255.255.240" 207 iip="192.0.2.17" 208 209 setup_loopback 210 211 # Stop spoofing 212 ${fwcmd} add deny all from ${inet}:${imask} to any in via ${oif} 213 ${fwcmd} add deny all from ${onet}:${omask} to any in via ${iif} 214 215 # Stop RFC1918 nets on the outside interface 216 ${fwcmd} add deny all from any to 10.0.0.0/8 via ${oif} 217 ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} 218 ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} 219 220 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 221 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 222 # on the outside interface 223 ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} 224 ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} 225 ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} 226 ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} 227 ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} 228 229 # Network Address Translation. This rule is placed here deliberately 230 # so that it does not interfere with the surrounding address-checking 231 # rules. If for example one of your internal LAN machines had its IP 232 # address set to 192.0.2.1 then an incoming packet for it after being 233 # translated by natd(8) would match the `deny' rule above. Similarly 234 # an outgoing packet originated from it before being translated would 235 # match the `deny' rule below. 236 case ${natd_enable} in 237 [Yy][Ee][Ss]) 238 if [ -n "${natd_interface}" ]; then 239 ${fwcmd} add divert natd all from any to any via ${natd_interface} 240 fi 241 ;; 242 esac 243 244 # Stop RFC1918 nets on the outside interface 245 ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} 246 ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} 247 ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} 248 249 # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, 250 # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) 251 # on the outside interface 252 ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} 253 ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} 254 ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} 255 ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} 256 ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} 257 258 # Allow TCP through if setup succeeded 259 ${fwcmd} add pass tcp from any to any established 260 261 # Allow IP fragments to pass through 262 ${fwcmd} add pass all from any to any frag 263 264 # Allow setup of incoming email 265 ${fwcmd} add pass tcp from any to ${oip} 25 setup 266 267 # Allow access to our DNS 268 ${fwcmd} add pass tcp from any to ${oip} 53 setup 269 ${fwcmd} add pass udp from any to ${oip} 53 270 ${fwcmd} add pass udp from ${oip} 53 to any 271 272 # Allow access to our WWW 273 ${fwcmd} add pass tcp from any to ${oip} 80 setup 274 275 # Reject&Log all setup of incoming connections from the outside 276 ${fwcmd} add deny log tcp from any to any in via ${oif} setup 277 278 # Allow setup of any other TCP connection 279 ${fwcmd} add pass tcp from any to any setup 280 281 # Allow DNS queries out in the world 282 ${fwcmd} add pass udp from ${oip} to any 53 keep-state 283 284 # Allow NTP queries out in the world 285 ${fwcmd} add pass udp from ${oip} to any 123 keep-state 286 287 # Everything else is denied by default, unless the 288 # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel 289 # config file. 290 ;; 291 292[Cc][Ll][Oo][Ss][Ee][Dd]) 293 setup_loopback 294 ;; 295[Uu][Nn][Kk][Nn][Oo][Ww][Nn]) 296 ;; 297*) 298 if [ -r "${firewall_type}" ]; then 299 ${fwcmd} ${firewall_flags} ${firewall_type} 300 fi 301 ;; 302esac 303