rc.firewall revision 25184 
1############
2# Setup system for firewall service.
3# $Id: rc.firewall,v 1.8 1997/02/23 09:20:47 peter 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#
27# For a more advanced treatment of Internet Security read:
28#
29#	Firewalls & Internet Security
30#	Repelling the wily hacker
31#	William R. Cheswick, Steven M. Bellowin
32#
33#	Addison-Wesley
34#	ISBN 0-201-6337-4
35#
36
37############
38# Flush out the list before we begin.
39/sbin/ipfw -f flush
40
41############
42# If you just configured ipfw in the kernel as a tool to solve network
43# problems or you just want to disallow some particular kinds of traffic
44# they you will want to change the default policy to open.  You can also
45# do this as your only action by setting the firewall_type to ``open''.
46
47# /sbin/ipfw add 65000 pass all from any to any
48
49############
50# Only in rare cases do you want to change this rule
51/sbin/ipfw add 1000 pass all from 127.0.0.1 to 127.0.0.1
52
53
54# Prototype setups.
55if [ "${firewall}" = "open" ]; then
56
57	/sbin/ipfw add 65000 pass all from any to any
58
59elif [ "${firewall}" = "client" ]; then
60
61    ############
62    # This is a prototype setup that will protect your system somewhat against
63    # people from outside your own network.
64    ############
65
66    # set these to your network and netmask and ip
67    net="192.168.4.0"
68    mask="255.255.255.0"
69    ip="192.168.4.17"
70
71    # Allow any traffic to or from my own net.
72    /sbin/ipfw add pass all from ${ip} to ${net}:${mask}
73    /sbin/ipfw add pass all from ${net}:${mask} to ${ip}
74
75    # Allow TCP through if setup succeeded
76    /sbin/ipfw add pass tcp from any to any established
77
78    # Allow setup of incoming email 
79    /sbin/ipfw add pass tcp from any to ${ip} 25 setup
80
81    # Allow setup of outgoing TCP connections only
82    /sbin/ipfw add pass tcp from ${ip} to any setup
83
84    # Disallow setup of all other TCP connections
85    /sbin/ipfw add deny tcp from any to any setup
86
87    # Allow DNS queries out in the world
88    /sbin/ipfw add pass udp from any 53 to ${ip}
89    /sbin/ipfw add pass udp from ${ip} to any 53
90
91    # Allow NTP queries out in the world
92    /sbin/ipfw add pass udp from any 123 to ${ip}
93    /sbin/ipfw add pass udp from ${ip} to any 123
94
95    # Everyting else is denied as default.
96
97elif [ "${firewall}" = "simple" ]; then
98
99    ############
100    # This is a prototype setup for a simple firewall.  Configure this machine 
101    # as a named server and ntp server, and point all the machines on the inside
102    # at this machine for those services.
103    ############
104
105    # set these to your outside interface network and netmask and ip
106    oif="ed0"
107    onet="192.168.4.0"
108    omask="255.255.255.0"
109    oip="192.168.4.17"
110
111    # set these to your inside interface network and netmask and ip
112    iif="ed1"
113    inet="192.168.3.0"
114    imask="255.255.255.0"
115    iip="192.168.3.17"
116
117    # Stop spoofing
118    /sbin/ipfw add deny all from ${inet}:${imask} to any in via ${oif}
119    /sbin/ipfw add deny all from ${onet}:${omask} to any in via ${iif}
120
121    # Stop RFC1918 nets on the outside interface
122    /sbin/ipfw add deny all from 192.168.0.0:255.255.0.0 to any via ${oif}
123    /sbin/ipfw add deny all from 172.16.0.0:255.240.0.0 to any via ${oif}
124    /sbin/ipfw add deny all from 10.0.0.0:255.0.0.0 to any via ${oif}
125
126    # Allow TCP through if setup succeeded
127    /sbin/ipfw add pass tcp from any to any established
128
129    # Allow setup of incoming email 
130    /sbin/ipfw add pass tcp from any to ${oip} 25 setup
131
132    # Allow access to our DNS
133    /sbin/ipfw add pass tcp from any to ${oip} 53 setup
134
135    # Allow access to our WWW
136    /sbin/ipfw add pass tcp from any to ${oip} 80 setup
137
138    # Reject&Log all setup of incoming connections from the outside
139    /sbin/ipfw add deny log tcp from any to any in via ${oif} setup
140
141    # Allow setup of any other TCP connection
142    /sbin/ipfw add pass tcp from any to any setup
143
144    # Allow DNS queries out in the world
145    /sbin/ipfw add pass udp from any 53 to ${oip}
146    /sbin/ipfw add pass udp from ${oip} to any 53
147
148    # Allow NTP queries out in the world
149    /sbin/ipfw add pass udp from any 123 to ${oip}
150    /sbin/ipfw add pass udp from ${oip} to any 123
151
152    # Everyting else is denied as default.
153fi
154
155