rc.firewall revision 25478 
1############
2# Setup system for firewall service.
3# $Id: rc.firewall,v 1.11 1997/05/03 11:22:17 jkh Exp $
4
5############
6#
7# >>Warning<<
8# This file is not very old yet, and have been put together without much
9# testing of the contents.
10
11# Set this to be the type of firewall you want:  open, client, simple or NONE.
12# ``open'' will allow anyone in, ``client'' will try to protect just one
13# machine and ``simple'' will try to protect a whole network (entries should
14# be customized appropriately below).  To let no one in, use NONE.
15
16############
17#
18# If you don't know enough about packet filtering, we suggest that you
19# take time to read this book:
20#
21#	Building Internet Firewalls
22#	Brent Chapman and Elizabeth Zwicky
23#
24#	O'Reilly & Associates, Inc
25#	ISBN 1-56592-124-0
26#	http://www.ora.com/
27#
28# For a more advanced treatment of Internet Security read:
29#
30#	Firewalls & Internet Security
31#	Repelling the wily hacker
32#	William R. Cheswick, Steven M. Bellowin
33#
34#	Addison-Wesley
35#	ISBN 0-201-6337-4
36#	http://www.awl.com/
37#
38
39############
40# Flush out the list before we begin.
41/sbin/ipfw -f flush
42
43############
44# If you just configured ipfw in the kernel as a tool to solve network
45# problems or you just want to disallow some particular kinds of traffic
46# they you will want to change the default policy to open.  You can also
47# do this as your only action by setting the firewall_type to ``open''.
48
49# /sbin/ipfw add 65000 pass all from any to any
50
51############
52# Only in rare cases do you want to change this rule
53/sbin/ipfw add 1000 pass all from 127.0.0.1 to 127.0.0.1
54
55
56# Prototype setups.
57if [ "${firewall}" = "open" ]; then
58
59	/sbin/ipfw add 65000 pass all from any to any
60
61elif [ "${firewall}" = "client" ]; then
62
63    ############
64    # This is a prototype setup that will protect your system somewhat against
65    # people from outside your own network.
66    ############
67
68    # set these to your network and netmask and ip
69    net="192.168.4.0"
70    mask="255.255.255.0"
71    ip="192.168.4.17"
72
73    # Allow any traffic to or from my own net.
74    /sbin/ipfw add pass all from ${ip} to ${net}:${mask}
75    /sbin/ipfw add pass all from ${net}:${mask} to ${ip}
76
77    # Allow TCP through if setup succeeded
78    /sbin/ipfw add pass tcp from any to any established
79
80    # Allow setup of incoming email 
81    /sbin/ipfw add pass tcp from any to ${ip} 25 setup
82
83    # Allow setup of outgoing TCP connections only
84    /sbin/ipfw add pass tcp from ${ip} to any setup
85
86    # Disallow setup of all other TCP connections
87    /sbin/ipfw add deny tcp from any to any setup
88
89    # Allow DNS queries out in the world
90    /sbin/ipfw add pass udp from any 53 to ${ip}
91    /sbin/ipfw add pass udp from ${ip} to any 53
92
93    # Allow NTP queries out in the world
94    /sbin/ipfw add pass udp from any 123 to ${ip}
95    /sbin/ipfw add pass udp from ${ip} to any 123
96
97    # Everything else is denied as default.
98
99elif [ "${firewall}" = "simple" ]; then
100
101    ############
102    # This is a prototype setup for a simple firewall.  Configure this machine 
103    # as a named server and ntp server, and point all the machines on the inside
104    # at this machine for those services.
105    ############
106
107    # set these to your outside interface network and netmask and ip
108    oif="ed0"
109    onet="192.168.4.0"
110    omask="255.255.255.0"
111    oip="192.168.4.17"
112
113    # set these to your inside interface network and netmask and ip
114    iif="ed1"
115    inet="192.168.3.0"
116    imask="255.255.255.0"
117    iip="192.168.3.17"
118
119    # Stop spoofing
120    /sbin/ipfw add deny all from ${inet}:${imask} to any in via ${oif}
121    /sbin/ipfw add deny all from ${onet}:${omask} to any in via ${iif}
122
123    # Stop RFC1918 nets on the outside interface
124    /sbin/ipfw add deny all from 192.168.0.0:255.255.0.0 to any via ${oif}
125    /sbin/ipfw add deny all from 172.16.0.0:255.240.0.0 to any via ${oif}
126    /sbin/ipfw add deny all from 10.0.0.0:255.0.0.0 to any via ${oif}
127
128    # Allow TCP through if setup succeeded
129    /sbin/ipfw add pass tcp from any to any established
130
131    # Allow setup of incoming email 
132    /sbin/ipfw add pass tcp from any to ${oip} 25 setup
133
134    # Allow access to our DNS
135    /sbin/ipfw add pass tcp from any to ${oip} 53 setup
136
137    # Allow access to our WWW
138    /sbin/ipfw add pass tcp from any to ${oip} 80 setup
139
140    # Reject&Log all setup of incoming connections from the outside
141    /sbin/ipfw add deny log tcp from any to any in via ${oif} setup
142
143    # Allow setup of any other TCP connection
144    /sbin/ipfw add pass tcp from any to any setup
145
146    # Allow DNS queries out in the world
147    /sbin/ipfw add pass udp from any 53 to ${oip}
148    /sbin/ipfw add pass udp from ${oip} to any 53
149
150    # Allow NTP queries out in the world
151    /sbin/ipfw add pass udp from any 123 to ${oip}
152    /sbin/ipfw add pass udp from ${oip} to any 123
153
154    # Everything else is denied as default.
155
156elif [ "${firewall}" != "NONE" -a -r "${firewall}" ]; then
157
158	/sbin/ipfw ${firewall}
159fi
160