7d79f25eed
Added links to O'Reilly & Associates and Addison-Wesley's web sites to accompany the book recommendations.
157 lines
4.7 KiB
Plaintext
157 lines
4.7 KiB
Plaintext
############
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# Setup system for firewall service.
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# $Id: rc.firewall,v 1.9 1997/04/27 03:59:14 jkh Exp $
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############
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#
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# >>Warning<<
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# This file is not very old yet, and have been put together without much
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# testing of the contents.
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# Set this to be the type of firewall you want: open, client, simple or NONE.
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# ``open'' will allow anyone in, ``client'' will try to protect just one
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# machine and ``simple'' will try to protect a whole network (entries should
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# be customized appropriately below). To let no one in, use NONE.
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############
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#
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# If you don't know enough about packet filtering, we suggest that you
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# take time to read this book:
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#
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# Building Internet Firewalls
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# Brent Chapman and Elizabeth Zwicky
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#
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# O'Reilly & Associates, Inc
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# ISBN 1-56592-124-0
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# http://www.ora.com
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#
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# For a more advanced treatment of Internet Security read:
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#
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# Firewalls & Internet Security
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# Repelling the wily hacker
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# William R. Cheswick, Steven M. Bellowin
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#
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# Addison-Wesley
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# ISBN 0-201-6337-4
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# http://www.awl.com
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#
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############
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# Flush out the list before we begin.
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/sbin/ipfw -f flush
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############
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# If you just configured ipfw in the kernel as a tool to solve network
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# problems or you just want to disallow some particular kinds of traffic
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# they you will want to change the default policy to open. You can also
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# do this as your only action by setting the firewall_type to ``open''.
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# /sbin/ipfw add 65000 pass all from any to any
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############
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# Only in rare cases do you want to change this rule
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/sbin/ipfw add 1000 pass all from 127.0.0.1 to 127.0.0.1
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# Prototype setups.
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if [ "${firewall}" = "open" ]; then
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/sbin/ipfw add 65000 pass all from any to any
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elif [ "${firewall}" = "client" ]; then
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############
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# This is a prototype setup that will protect your system somewhat against
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# people from outside your own network.
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############
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# set these to your network and netmask and ip
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net="192.168.4.0"
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mask="255.255.255.0"
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ip="192.168.4.17"
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# Allow any traffic to or from my own net.
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/sbin/ipfw add pass all from ${ip} to ${net}:${mask}
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/sbin/ipfw add pass all from ${net}:${mask} to ${ip}
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# Allow TCP through if setup succeeded
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/sbin/ipfw add pass tcp from any to any established
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# Allow setup of incoming email
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/sbin/ipfw add pass tcp from any to ${ip} 25 setup
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# Allow setup of outgoing TCP connections only
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/sbin/ipfw add pass tcp from ${ip} to any setup
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# Disallow setup of all other TCP connections
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/sbin/ipfw add deny tcp from any to any setup
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# Allow DNS queries out in the world
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/sbin/ipfw add pass udp from any 53 to ${ip}
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/sbin/ipfw add pass udp from ${ip} to any 53
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# Allow NTP queries out in the world
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/sbin/ipfw add pass udp from any 123 to ${ip}
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/sbin/ipfw add pass udp from ${ip} to any 123
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# Everything else is denied as default.
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elif [ "${firewall}" = "simple" ]; then
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############
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# This is a prototype setup for a simple firewall. Configure this machine
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# as a named server and ntp server, and point all the machines on the inside
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# at this machine for those services.
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############
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# set these to your outside interface network and netmask and ip
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oif="ed0"
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onet="192.168.4.0"
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omask="255.255.255.0"
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oip="192.168.4.17"
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# set these to your inside interface network and netmask and ip
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iif="ed1"
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inet="192.168.3.0"
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imask="255.255.255.0"
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iip="192.168.3.17"
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# Stop spoofing
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/sbin/ipfw add deny all from ${inet}:${imask} to any in via ${oif}
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/sbin/ipfw add deny all from ${onet}:${omask} to any in via ${iif}
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# Stop RFC1918 nets on the outside interface
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/sbin/ipfw add deny all from 192.168.0.0:255.255.0.0 to any via ${oif}
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/sbin/ipfw add deny all from 172.16.0.0:255.240.0.0 to any via ${oif}
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/sbin/ipfw add deny all from 10.0.0.0:255.0.0.0 to any via ${oif}
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# Allow TCP through if setup succeeded
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/sbin/ipfw add pass tcp from any to any established
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# Allow setup of incoming email
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/sbin/ipfw add pass tcp from any to ${oip} 25 setup
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# Allow access to our DNS
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/sbin/ipfw add pass tcp from any to ${oip} 53 setup
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# Allow access to our WWW
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/sbin/ipfw add pass tcp from any to ${oip} 80 setup
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# Reject&Log all setup of incoming connections from the outside
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/sbin/ipfw add deny log tcp from any to any in via ${oif} setup
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# Allow setup of any other TCP connection
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/sbin/ipfw add pass tcp from any to any setup
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# Allow DNS queries out in the world
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/sbin/ipfw add pass udp from any 53 to ${oip}
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/sbin/ipfw add pass udp from ${oip} to any 53
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# Allow NTP queries out in the world
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/sbin/ipfw add pass udp from any 123 to ${oip}
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/sbin/ipfw add pass udp from ${oip} to any 123
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# Everything else is denied as default.
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fi
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