Date: Thu, 10 Feb 2000 21:18:41 -0800 From: chip <chip@wiegand.org> To: keramida@ceid.upatras.gr Cc: questions@freebsd.org Subject: Re: rc.firewall problem - Take 4 Message-ID: <38A39BB1.17ED9740@wiegand.org> References: <20000208040302.B10648@hades.hell.gr> <00020800084901.02763@firewall.homenet> <20000210162740.A13143@hades.hell.gr>
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This is a multi-part message in MIME format. --------------EF1CA0816D548B6D5DF63F93 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Thanks for the suggestion of using ifpw show, I didn't know that command. I have attached two files - the results of running ipfw show as a text doc and my rc.firewall file. I hope these are readable. I thought it would be better to attach them than to copy the whole text into the message. Chip W Giorgos Keramidas wrote: > On Mon, Feb 07, 2000 at 11:39:33PM -0800, Chip wrote: > > > > I still have a problem though. When I try to ping another machine on > > my network I get the following message: > > > > ping: sendto: Permission denied > > > > I can ping the nics in that machine though. I believe this may be > > because icmp is blocked by the firewall? > > Without the actual rules, as printed by `ipfw show' there isn't much I > can guess about why ping fails to work. Blocked icmp's could be a > reason, though. > > -- > Giorgos Keramidas, < keramida @ ceid . upatras . gr > > For my public PGP key: finger keramida@diogenis.ceid.upatras.gr > PGP fingerprint, phone and address in the headers of this message. --------------EF1CA0816D548B6D5DF63F93 Content-Type: text/plain; charset=us-ascii; name="rc.firewall" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="rc.firewall" ############ # Setup system for firewall service. # $FreeBSD: src/etc/rc.firewall,v 1.19.2.2 1999/08/29 14:18:55 peter Exp $ # Suck in the configuration variables. if [ -f /etc/defaults/rc.conf ]; then . /etc/defaults/rc.conf elif [ -f /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 [ "x$1" != "x" ]; then firewall_type=$1 fi ############ # Set quiet mode if requested if [ "x$firewall_quiet" = "xYES" ]; then fwcmd="/sbin/ipfw -q" else fwcmd="/sbin/ipfw" fi ############ # Flush out the list before we begin. $fwcmd -f flush ############ # These rules are required for using natd. All packets are passed to # natd before they encounter your remaining rules. The firewall rules # will then be run again on each packet after translation by natd, # minus any divert rules (see natd(8)). if [ "X${natd_enable}" = X"YES" -a "X${natd_interface}" != X"" ]; then $fwcmd add divert natd all from any to any via ${natd_interface} fi ############ # 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. You can also # do this as your only action by setting the firewall_type to ``open''. # $fwcmd add 65000 pass all from any to any ############ # Only in rare cases do you want to change these rules $fwcmd add 100 pass all from any to any via lo0 $fwcmd add 200 deny all from any to 127.0.0.0/8 # Prototype setups. if [ "${firewall_type}" = "open" -o "${firewall_type}" = "OPEN" ]; then $fwcmd add 65000 pass all from any to any elif [ "${firewall_type}" = "client" ]; then ############ # This is a prototype setup that will protect your system somewhat against # people from outside your own network. ############ # set these to your network and netmask and ip net="192.168.0.1" mask="255.255.255.0" ip="192.168.0.1" # Allow any traffic to or from my own net. $fwcmd add pass all from ${ip} to ${net}:${mask} $fwcmd add pass all from ${net}:${mask} to ${ip} # Allow TCP through if setup succeeded $fwcmd add pass tcp from any to any established # Allow setup of incoming email $fwcmd add pass tcp from any to ${ip} 25 setup # Allow setup of outgoing TCP connections only $fwcmd add pass tcp from ${ip} to any setup # Disallow setup of all other TCP connections $fwcmd add deny tcp from any to any setup # Allow DNS queries out in the world $fwcmd add pass udp from any 53 to ${ip} $fwcmd add pass udp from ${ip} to any 53 # Allow NTP queries out in the world $fwcmd add pass udp from any 123 to ${ip} $fwcmd add pass udp from ${ip} to any 123 # Everything else is denied as default. elif [ "${firewall_type}" = "simple" ]; then ############ # 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. ############ # set these to your outside interface network and netmask and ip oif="mx0" onet="208.194.173.26" omask="255.255.255.128" oip="208.194.173.26" # set these to your inside interface network and netmask and ip iif="pn0" inet="192.168.0.1" imask="255.255.255.0" iip="192.168.0.1" # Stop spoofing $fwcmd add deny all from ${inet}:${imask} to any in via ${oif} $fwcmd add deny all from ${onet}:${omask} to any in via ${iif} # Stop RFC1918 nets on the outside interface $fwcmd add deny all from 192.168.0.0:255.255.0.0 to any via ${oif} $fwcmd add deny all from any to 192.168.0.0:255.255.0.0 via ${oif} $fwcmd add deny all from 172.16.0.0:255.240.0.0 to any via ${oif} $fwcmd add deny all from any to 172.16.0.0:255.240.0.0 via ${oif} $fwcmd add deny all from 10.0.0.0:255.0.0.0 to any via ${oif} $fwcmd add deny all from any to 10.0.0.0:255.0.0.0 via ${oif} # Allow TCP through if setup succeeded $fwcmd add pass tcp from any to any established # Allow setup of incoming email $fwcmd add pass tcp from any to ${oip} 25 setup # Allow access to our DNS $fwcmd add pass tcp from any to ${oip} 53 setup # Allow access to our WWW $fwcmd add pass tcp from any to ${oip} 80 setup # Reject&Log all setup of incoming connections from the outside $fwcmd add deny log tcp from any to any in via ${oif} setup # Allow setup of any other TCP connection $fwcmd add pass tcp from any to any setup # Allow DNS queries out in the world $fwcmd add pass udp from any 53 to ${oip} $fwcmd add pass udp from ${oip} to any 53 # Allow NTP queries out in the world $fwcmd add pass udp from any 123 to ${oip} $fwcmd add pass udp from ${oip} to any 123 # Everything else is denied as default. elif [ "${firewall_type}" != "UNKNOWN" -a -r "${firewall_type}" ]; then $fwcmd ${firewall_type} fi --------------EF1CA0816D548B6D5DF63F93 Content-Type: text/plain; charset=us-ascii; name="ipfw_show.txt" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="ipfw_show.txt" chip# ipfw show 00100 0 0 allow ip from any to any via lo0 00200 0 0 deny ip from any to 127.0.0.0/8 00300 0 0 deny ip from 192.168.0.0/24 to any in recv mx0 00400 0 0 deny ip from 208.194.173.0/25 to any in recv pn0 00500 30 7265 deny ip from 192.168.0.0/16 to any via mx0 00600 0 0 deny ip from any to 192.168.0.0/16 via mx0 00700 0 0 deny ip from 172.16.0.0/12 to any via mx0 00800 0 0 deny ip from any to 172.16.0.0/12 via mx0 00900 0 0 deny ip from 10.0.0.0/8 to any via mx0 01000 0 0 deny ip from any to 10.0.0.0/8 via mx0 01100 23 7274 allow tcp from any to any established 01200 0 0 allow tcp from any to 208.194.173.26 25 setup 01300 0 0 allow tcp from any to 208.194.173.26 53 setup 01400 0 0 allow tcp from any to 208.194.173.26 80 setup 01500 0 0 deny log logamount 100 tcp from any to any in recv mx0 setup 01600 8 384 allow tcp from any to any setup 01700 0 0 allow udp from any 53 to 208.194.173.26 01800 0 0 allow udp from 208.194.173.26 to any 53 01900 0 0 allow udp from any 123 to 208.194.173.26 02000 0 0 allow udp from 208.194.173.26 to any 123 65535 36 2634 deny ip from any to any --------------EF1CA0816D548B6D5DF63F93-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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