rc.firewall revision 15027 
1############
2# Setup system for firewall service.
3# $Id$
4
5############
6#
7# >>Warning<<
8# This file is not very old yet, and have been put together without much
9# test of the contents.
10
11############
12#
13# If you don't know enough about packet filtering, we suggest that you
14# take time to read this book:
15#
16#	Firewalls & Internet Security
17#	Repelling the wily hacker
18#	William R. Cheswick, Steven M. Bellowin
19#
20#	Addison-Wesley
21#	ISBN 0-201-6337-4
22#
23
24############
25# If you just configured ipfw in the kernel as a tool to solve network
26# problems or you just want to disallow some particular kinds of traffic
27# they you will want to change the default policy to open.
28
29# /sbin/ipfw add 65000 pass all from any to any
30
31############
32# Only in rare cases do you want to change this rule
33/sbin/ipfw add 1000 pass all from 127.0.0.1 to 127.0.0.1
34
35############
36# This is a prototype setup that will protect your system somewhat against
37# people from outside your own network.
38#
39# To enable simply change "false" to "true" in the if line and set the
40# variables to your network parameters
41
42if false ; then
43    # set these to your network and netmask and ip
44    net="192.168.4.0"
45    mask="255.255.255.0"
46    ip="192.168.4.17"
47
48    # Allow any traffic to or from my own net.
49    /sbin/ipfw add pass all from ${ip} to ${net}:${mask}
50    /sbin/ipfw add pass all from ${net}:${mask} to ${ip}
51
52    # Allow TCP through if setup succeeded
53    /sbin/ipfw add deny tcp from any to any established
54
55    # Allow setup of incoming email 
56    /sbin/ipfw add pass tcp from any to ${ip} 25 setup
57
58    # Allow setup of outgoing TCP connections only
59    /sbin/ipfw add pass tcp from ${ip} to any setup
60
61    # Disallow setup of all other TCP connections
62    /sbin/ipfw add deny tcp from any to any setup
63
64    # Allow DNS queries out in the world
65    /sbin/ipfw add pass udp from any 53 to ${ip}
66    /sbin/ipfw add pass udp from ${ip} to any 53
67
68    # Allow NTP queries out in the world
69    /sbin/ipfw add pass udp from any 123 to ${ip}
70    /sbin/ipfw add pass udp from ${ip} to any 123
71
72    # Everyting else is denied as default.
73fi
74
75############
76# This is a prototype setup for a simple firewall.  Configure this machine 
77# as a named server and ntp server, and point all the machines on the inside
78# at this machine for those services.
79#
80# To enable simply change "false" to "true" in the if line and set the
81# variables to your network parameters
82
83if false ; then
84    # set these to your outside interface network and netmask and ip
85    oif="ed0"
86    onet="192.168.4.0"
87    omask="255.255.255.0"
88    oip="192.168.4.17"
89
90    # set these to your inside interface network and netmask and ip
91    iif="ed1"
92    inet="192.168.3.0"
93    imask="255.255.255.0"
94    iip="192.168.3.17"
95
96    # Stop spoofing
97    /sbin/ipfw add deny all from ${inet}:${imask} to any in via ${oif}
98    /sbin/ipfw add deny all from ${onet}:${omask} to any in via ${iif}
99
100    # Stop RFC1918 nets on the outside interface
101    /sbin/ipfw add deny all from 192.168.0.0:255.255.0.0 to any via ${oif}
102    /sbin/ipfw add deny all from 172.16.0.0:255.240.0.0 to any via ${oif}
103    /sbin/ipfw add deny all from 10.0.0.0:255.0.0.0 to any via ${oif}
104
105    # Allow TCP through if setup succeeded
106    /sbin/ipfw add deny tcp from any to any established
107
108    # Allow setup of incoming email 
109    /sbin/ipfw add pass tcp from any to ${oip} 25 setup
110
111    # Allow access to our DNS
112    /sbin/ipfw add pass tcp from any to ${oip} 53 setup
113
114    # Allow access to our WWW
115    /sbin/ipfw add pass tcp from any to ${oip} 80 setup
116
117    # Reject&Log all setup of incoming connections from the outside
118    /sbin/ipfw add deny log tcp from any to any in via ${oif} setup
119
120    # Allow setup of any other TCP connection
121    /sbin/ipfw add pass tcp from any to any setup
122
123    # Allow DNS queries out in the world
124    /sbin/ipfw add pass udp from any 53 to ${oip}
125    /sbin/ipfw add pass udp from ${oip} to any 53
126
127    # Allow NTP queries out in the world
128    /sbin/ipfw add pass udp from any 123 to ${oip}
129    /sbin/ipfw add pass udp from ${oip} to any 123
130
131    # Everyting else is denied as default.
132fi
133
134