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Date:      Wed, 20 Sep 2000 08:49:42 -0700 (PDT)
From:      The Utz Family <utz@serv.net>
To:        "seafug@dub.net" <seafug@dub.net>
Cc:        Chip <chip@wiegand.org>, "freebsd-questions@freebsd.org" <freebsd-questions@FreeBSD.ORG>
Subject:   what about ppp -alias? Re: natd does port forwarding?
Message-ID:  <Pine.BSF.4.02.10009200848350.55933-100000@itchy.serv.net>
In-Reply-To: <20000919232213.Q367@149.211.6.64.reflexcom.com>

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ok, 

so is natd a superior solution to the userland ppp forwarding? if so, why?

pontificate away! :-)

On 19 Sep 2000, Crist J . Clark wrote:

> On Tue, Sep 19, 2000 at 10:25:31PM -0700, Chip wrote:
> > According to top natd is running, in fact, after a reboot it
> > showed two instances of it running. I have attached my rc.conf,
> > rc.firewall, and natd.conf in the hopes that someone can tell
> > me where I have gone wrong, because port forwarding is not
> > working.
> 
> OK, I made some observations. What version of FreeBSD are you using,
> BTW?
> 
> > More details in the text below for any new readers.
> > The firewall is basically the default, I will tighten up the
> > rules 
> > after I get port-forwarding running.
> 
> Loosen them up first to get things going, but I mentioned that below.
> 
> > Any help would be greatly appreciated.
> 
> [snip]
> 
> > natd.conf --
> >
> > use_sockets yes
> > same_ports yes
> > interface ep1
> > redirect_port tcp 192.168.0.7:80 80
> 
> > rc.conf --
> >
> > # This file now contains just the overrides from /etc/defaults/rc.conf
> > # please make all changes to this file.
> > 
> > # -- sysinstall generated deltas -- #
> > ifconfig_xl0="inet 192.168.0.1  netmask 255.255.255.0"
> > ifconfig_ep1="inet 208.194.173.26 netmask 255.255.255.128"
> > hostname="firewall2.wiegand.org"
> > linux_enable="YES"
> > moused_enable="YES"
> > firewall_enable="YES"
> > firewall_script="/etc/rc.firewall"
> > firewall_type="simple"
> 
> Open things up to get them working first,
> 
>   firewall_type="open"
> 
> > gateway_enable="YES"
> > router_enable="YES"
> 
> Remove this. It is not needed.
> 
> > defaultrouter="208.194.173.1"
> > natd_enable="YES"
> > natd_interface="ep1"
> 
> You forgot,
> 
>   natd_flags="-f /etc/natd.conf"
> 
> > rc.firewall --
> >
> > ############
> > # Setup system for firewall service.
> > # $FreeBSD: src/etc/rc.firewall,v 1.30 2000/02/06 19:24:37 paul Exp $
> > 
> > # Suck in the configuration variables.
> > if [ -r /etc/defaults/rc.conf ]; then
> > 	. /etc/defaults/rc.conf
> > if [ -r /etc/rc.conf ]; then
> > 	. /etc/rc.conf
> > fi
> > 
> > ############
> > # Define the firewall type in /etc/rc.conf.  Valid values are:
> > #   open     - will allow anyone in
> > #   client   - will try to protect just this machine
> > #   simple   - will try to protect a whole network
> > #   closed   - totally disables IP services except via lo0 interface
> > #   UNKNOWN  - disables the loading of firewall rules.
> > #   filename - will load the rules in the given filename (full path required)
> > #
> > # For ``client'' and ``simple'' the entries below should be customized
> > # appropriately.
> > 
> > ############
> > #
> > # If you don't know enough about packet filtering, we suggest that you
> > # take time to read this book:
> > #
> > #	Building Internet Firewalls
> > #	Brent Chapman and Elizabeth Zwicky
> > #
> > #	O'Reilly & Associates, Inc
> > #	ISBN 1-56592-124-0
> > #	http://www.ora.com/
> > #
> > # For a more advanced treatment of Internet Security read:
> > #
> > #	Firewalls & Internet Security
> > #	Repelling the wily hacker
> > #	William R. Cheswick, Steven M. Bellowin
> > #
> > #	Addison-Wesley
> > #	ISBN 0-201-6337-4
> > #	http://www.awl.com/
> > #
> > 
> > if [ -n "${1}" ]; then
> > 	ifirewall_type="${1}"
> > fi
> > 
> > ############
> > # Set quiet mode if requested
> > #
> > case ${firewall_quiet} in
> > [Yy][Ee][Ss])
> > 	fwcmd="/sbin/ipfw -q"
> > 	;;
> > *)
> > 	ifwcmd="/sbin/ipfw"
> > 	;;
> > esac
> > 
> > ############
> > # Flush out the list before we begin.
> > #
> > /sbin/ipfw -f flush
> > 
> > ############
> > # These rules are required for using natd.  All packets are passed to
> > # natd before they encounter your remaining rules.  The firewall rules
> > # will then be run again on each packet after translation by natd,
> > # minus any divert rules (see natd(8)).
> > #
> > #case ${natd_enable} in
> > #[Yy][Ee][Ss])
> > #	if [ -n "ep1" ]; then
> >         /sbin/ipfw add divert natd all from any to any via ep1		
> > #fi
> > #	;;
> > #esac
> 
> This has been modified.
> 
> > ############
> > # If you just configured ipfw in the kernel as a tool to solve network
> > # problems or you just want to disallow some particular kinds of traffic
> > # then you will want to change the default policy to open.  You can also
> > # do this as your only action by setting the firewall_type to ``open''.
> > #
> >      /sbin/ipfw add 65000 pass all from any to any
> 
> Why is this uncommented?
> 
> > ############
> > # Only in rare cases do you want to change these rules
> > #
> > /sbin/ipfw add 100 pass all from any to any via lo0
> > /sbin/ipfw add 200 deny all from any to 127.0.0.0/8
> > # If you're using 'options BRIDGE', uncomment the following line to pass ARP
> > #${fwcmd} add 300 pass udp from 0.0.0.0 2054 to 0.0.0.0
> > 
> > 
> > # Prototype setups.
> > #
> > case ${firewall_type} in
> > [Oo][Pp][Ee][Nn])
> > #if [ "${firewall}" = "open" ]; then
> 
> Hmmm...
> 
> > 	/sbin/ipfw add 65000 pass all from any to any
> > ;;	
> > 
> > [Cc][Ll][Ii][Ee][Nn][Tt])
> > 	############
> > 	# This is a prototype setup that will protect your system somewhat
> > 	# against people from outside your own network.
> > 	############
> > #elif [ "${firewall}" = "client" ]; then
> 
> This was in the default? What version again?
> 
> > 	# set these to your network and netmask and ip
> > 	net="192.168.0.0"
> > 	mask="255.255.255.0"
> > 	ip="192.168.0.1"
> > 
> > 	# 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 pass tcp from any to any established
> > 
> > 	# Allow IP fragments to pass through
> > 	/sbin/ipfw add pass all from any to any frag
> > 
> > 	# 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 ${ip} to any 123
> > 
> > 	# Everything else is denied by default, unless the
> > 	# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
> > 	# config file.
> > 	;;
> > 
> > [Ss][Ii][Mm][Pp][Ll][Ee])
> > 	############
> > 	# This is a prototype setup for a simple firewall.  Configure this
> > 	# machine as a named server and ntp server, and point all the machines
> > 	# on the inside at this machine for those services.
> > 	############
> > #elif [ "${firewall}" = "simple" ]; then
> > 	# set these to your outside interface network and netmask and ip
> > 	oif="ep1"
> > 	onet="208.240.173.0"
> > 	omask="255.255.255.128"
> > 	oip="208.240.173.26"
> 
> These numbers do not match the ones you gave above in rc.conf.
> 
> > 	# set these to your inside interface network and netmask and ip
> > 	iif="xl0"
> > 	inet="192.168.0.0"
> > 	imask="255.255.255.0"
> > 	iip="192.168.0.1"
> > 
> > 	# 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 10.0.0.0/8 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 10.0.0.0/8 via ${oif}
> > 	/sbin/ipfw add deny all from 172.16.0.0/12 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 172.16.0.0/12 via ${oif}
> > 	/sbin/ipfw add deny all from 192.168.0.0/16 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 192.168.0.0/16 via ${oif}
> > 
> > 	# Stop draft-manning-dsua-01.txt nets on the outside interface
> > 	/sbin/ipfw add deny all from 0.0.0.0/8 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 0.0.0.0/8 via ${oif}
> > 	/sbin/ipfw add deny all from 169.254.0.0/16 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 169.254.0.0/16 via ${oif}
> > 	/sbin/ipfw add deny all from 192.0.2.0/24 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 192.0.2.0/24 via ${oif}
> > 	/sbin/ipfw add deny all from 224.0.0.0/4 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 224.0.0.0/4 via ${oif}
> > 	/sbin/ipfw add deny all from 240.0.0.0/4 to any via ${oif}
> > 	/sbin/ipfw add deny all from any to 240.0.0.0/4 via ${oif}
> > 
> >         # Allow TCP through if setup succeeded
> > 	/sbin/ipfw add pass tcp from any to any established
> > 
> > 	# Allow IP fragments to pass through
> > 	/sbin/ipfw add pass all from any to any frag
> > 
> > 	# 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
> > 	/sbin/ipfw add pass udp from any to ${oip} 53
> > 	/sbin/ipfw add pass udp from ${oip} 53 to any
> > 
> > 	# 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 ${oip} to any 123
> > 
> > 	# Everything else is denied by default, unless the
> > 	# IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel
> > 	# config file.
> > 	;;
> >         fi
> > )
> > #[Uu][Nn][Kk][Nn][Oo][Ww][Nn])
> > 
> > 	;;
> > )
> > )
> > #	if [ -r "${firewall_type}" ]; then
> > 	/sbin/ipfw ${firewall_flags} ${firewall_type}
> > #        fi
> > 	;;
> > esac
> > fi
> 
> 
> -- 
> Crist J. Clark                           cjclark@alum.mit.edu
> 



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