diff --git a/etc/Makefile b/etc/Makefile
index 802e795c7043..b79696c81510 100644
--- a/etc/Makefile
+++ b/etc/Makefile
@@ -1,5 +1,5 @@
 #	from: @(#)Makefile	5.11 (Berkeley) 5/21/91
-#	$Id: Makefile,v 1.134 1996/03/17 20:37:03 phk Exp $
+#	$Id: Makefile,v 1.135 1996/03/22 17:28:07 nate Exp $
 
 # -rw-r--r--
 BINOWN= root
@@ -8,7 +8,8 @@ BIN1=   aliases amd.map csh.cshrc csh.login csh.logout dm.conf \
 	ftpusers gettytab group hosts host.conf hosts.equiv hosts.lpd \
 	inetd.conf login.access motd modems netstart networks \
 	newsyslog.conf phones pccard.conf.sample printcap profile protocols \
-	rc rc.local rc.pccard rc.serial etc.${MACHINE}/rc.${MACHINE} \
+	rc rc.firewall rc.local rc.pccard rc.serial \
+	etc.${MACHINE}/rc.${MACHINE} \
 	remote security services sysconfig shells \
 	syslog.conf ttys etc.${MACHINE}/disktab rpc make.conf \
 	${.CURDIR}/../gnu/usr.bin/man/manpath/manpath.config \
diff --git a/etc/netstart b/etc/netstart
index 9cdc1357a5bb..220bc1bfe3b8 100755
--- a/etc/netstart
+++ b/etc/netstart
@@ -1,6 +1,6 @@
 #!/bin/sh -
 #
-#	$Id: netstart,v 1.41 1996/02/09 12:45:37 jkh Exp $
+#	$Id: netstart,v 1.42 1996/02/11 04:07:25 jkh Exp $
 #	From: @(#)netstart	5.9 (Berkeley) 3/30/91
 
 # Note that almost all the user-configurable behavior is no longer in
@@ -23,6 +23,11 @@ if [ -n "$defaultdomainname" -a "x$defaultdomainname" != "xNO" ] ; then
 	domainname $defaultdomainname
 fi
 
+# If IP filtering
+if [ -n "$firewall" -a "x$firewall" != "xNO" -f /etc/rc.firewall ] ; then
+	sh /etc/rc.firewall
+fi
+
 #
 # XXX This is known to cause an error if /usr is nfs mounted since it
 # will not be available until after the network is up :-(.  Once the
diff --git a/etc/rc.firewall b/etc/rc.firewall
new file mode 100644
index 000000000000..026334c455d6
--- /dev/null
+++ b/etc/rc.firewall
@@ -0,0 +1,133 @@
+############
+# Setup system for firewall service.
+# $Id$
+
+############
+#
+# >>Warning<<
+# This file is not very old yet, and have been put together without much
+# test of the contents.
+
+############
+#
+# If you don't know enough about packet filtering, we suggest that you
+# take time to read this book:
+#
+#	Firewalls & Internet Security
+#	Repelling the wily hacker
+#	William R. Cheswick, Steven M. Bellowin
+#
+#	Addison-Wesley
+#	ISBN 0-201-6337-4
+#
+
+############
+# If you just configured ipfw in the kernel as a tool to solve network
+# problems or you just want to disallow some particular kinds of traffic
+# they you will want to change the default policy to open.
+
+# /sbin/ipfw add 65000 pass all from any to any
+
+############
+# Only in rare cases do you want to change this rule
+/sbin/ipfw add 1000 pass all from 127.0.0.1 to 127.0.0.1
+
+############
+# This is a prototype setup that will protect your system somewhat against
+# people from outside your own network.
+#
+# To enable simply change "false" to "true" in the if line and set the
+# variables to your network parameters
+
+if false ; then
+    # set these to your network and netmask and ip
+    net="192.168.4.0"
+    mask="255.255.255.0"
+    ip="192.168.4.17"
+
+    # Allow any traffic to or from my own net.
+    /sbin/ipfw add pass all from ${ip} to ${net}:${mask}
+    /sbin/ipfw add pass all from ${net}:${mask} to ${ip}
+
+    # Allow TCP through if setup succeeded
+    /sbin/ipfw add deny tcp from any to any established
+
+    # Allow setup of incoming email 
+    /sbin/ipfw add pass tcp from any to ${ip} 25 setup
+
+    # Allow setup of outgoing TCP connections only
+    /sbin/ipfw add pass tcp from ${ip} to any setup
+
+    # Disallow setup of all other TCP connections
+    /sbin/ipfw add deny tcp from any to any setup
+
+    # Allow DNS queries out in the world
+    /sbin/ipfw add pass udp from any 53 to ${ip}
+    /sbin/ipfw add pass udp from ${ip} to any 53
+
+    # Allow NTP queries out in the world
+    /sbin/ipfw add pass udp from any 123 to ${ip}
+    /sbin/ipfw add pass udp from ${ip} to any 123
+
+    # Everyting else is denied as default.
+fi
+
+############
+# This is a prototype setup for a simple firewall.  Configure this machine 
+# as a named server and ntp server, and point all the machines on the inside
+# at this machine for those services.
+#
+# To enable simply change "false" to "true" in the if line and set the
+# variables to your network parameters
+
+if false ; then
+    # set these to your outside interface network and netmask and ip
+    oif="ed0"
+    onet="192.168.4.0"
+    omask="255.255.255.0"
+    oip="192.168.4.17"
+
+    # set these to your inside interface network and netmask and ip
+    iif="ed1"
+    inet="192.168.3.0"
+    imask="255.255.255.0"
+    iip="192.168.3.17"
+
+    # Stop spoofing
+    /sbin/ipfw add deny all from ${inet}:${imask} to any in via ${oif}
+    /sbin/ipfw add deny all from ${onet}:${omask} to any in via ${iif}
+
+    # Stop RFC1918 nets on the outside interface
+    /sbin/ipfw add deny all from 192.168.0.0:255.255.0.0 to any via ${oif}
+    /sbin/ipfw add deny all from 172.16.0.0:255.240.0.0 to any via ${oif}
+    /sbin/ipfw add deny all from 10.0.0.0:255.0.0.0 to any via ${oif}
+
+    # Allow TCP through if setup succeeded
+    /sbin/ipfw add deny tcp from any to any established
+
+    # Allow setup of incoming email 
+    /sbin/ipfw add pass tcp from any to ${oip} 25 setup
+
+    # Allow access to our DNS
+    /sbin/ipfw add pass tcp from any to ${oip} 53 setup
+
+    # Allow access to our WWW
+    /sbin/ipfw add pass tcp from any to ${oip} 80 setup
+
+    # Reject&Log all setup of incoming connections from the outside
+    /sbin/ipfw add deny log tcp from any to any in via ${oif} setup
+
+    # Allow setup of any other TCP connection
+    /sbin/ipfw add pass tcp from any to any setup
+
+    # Allow DNS queries out in the world
+    /sbin/ipfw add pass udp from any 53 to ${oip}
+    /sbin/ipfw add pass udp from ${oip} to any 53
+
+    # Allow NTP queries out in the world
+    /sbin/ipfw add pass udp from any 123 to ${oip}
+    /sbin/ipfw add pass udp from ${oip} to any 123
+
+    # Everyting else is denied as default.
+fi
+
diff --git a/etc/sysconfig b/etc/sysconfig
index 1ea5f0fc671f..2cb5fc412198 100644
--- a/etc/sysconfig
+++ b/etc/sysconfig
@@ -4,7 +4,7 @@
 # This is sysconfig - a file full of useful variables that you can set 
 # to change the default startup behavior of your system.
 #
-#	$Id: sysconfig,v 1.41 1996/03/12 15:39:26 nate Exp $
+#	$Id: sysconfig,v 1.42 1996/03/14 18:24:07 nate Exp $
 
 ######################### Start Of Local Configuration Section ###########
 
@@ -191,6 +191,9 @@ kerberos_server=NO
 # If you want this host to be a gateway, set to YES.
 gateway=NO
 
+# If you want this host to be a firewall or otherwise filter IP, set to YES.
+firewall=NO
+
 # Set to YES if you wish to check quotas.  NOTE:  For now this probably
 # doesn't work and should be left disabled.
 check_quotas=NO