Date: Mon, 26 Apr 2004 08:53:20 +0200 From: "Christoph P. Kukulies" <kuku@kukulies.org> To: Lewis Thompson <lewiz@fajita.org> Cc: questions@freebsd.org Subject: Re: firewall settings and dhcpd Message-ID: <20040426065320.GB2917@kukulies.org> In-Reply-To: <20040425114452.GA41600@fajita.org> References: <200404251133.i3PBXMlV094799@www.kukulies.org> <20040425114452.GA41600@fajita.org>
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On Sun, Apr 25, 2004 at 12:44:52PM +0100, Lewis Thompson wrote: > On Sun, Apr 25, 2004 at 01:33:22PM +0200, Christoph Kukulies wrote: > > I'm getting this in my log/messages: > > > > Apr 25 13:25:42 mybox dhcpd: send_packet: Permission denied > > > > Could it be that a certain firewall setting or something missing > > would be causing this? > > Possibly. It might be worth including some details of your current > firewall settings. Thanks. Here goes: [Ss][Ii][Mm][Pp][Ll][Ee]) ############ # This is a prototype setup for a simple firewall. Configure this # machine as a DNS 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="tun0" onet=" 213.146.112.0" omask="255.255.255.0" oip=" 213.146.112.180" # set these to your inside interface network and netmask and ip iif="ed0" inet="192.168.0.0" imask="255.255.255.0" iip="192.168.0.1" wiif="wi0" winet="192.168.254.0" wimask="255.255.255.0" wiip="192.168.254.1" setup_loopback # 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 any to 10.0.0.0/8 via ${oif} ${fwcmd} add deny all from any to 172.16.0.0/12 via ${oif} ${fwcmd} add deny all from any to 192.168.0.0/16 via ${oif} # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) # on the outside interface ${fwcmd} add deny all from any to 0.0.0.0/8 via ${oif} ${fwcmd} add deny all from any to 169.254.0.0/16 via ${oif} ${fwcmd} add deny all from any to 192.0.2.0/24 via ${oif} ${fwcmd} add deny all from any to 224.0.0.0/4 via ${oif} ${fwcmd} add deny all from any to 240.0.0.0/4 via ${oif} # Network Address Translation. This rule is placed here deliberately # so that it does not interfere with the surrounding address-checking # rules. If for example one of your internal LAN machines had its IP # address set to 192.0.2.1 then an incoming packet for it after being # translated by natd(8) would match the `deny' rule above. Similarly # an outgoing packet originated from it before being translated would # match the `deny' rule below. case ${natd_enable} in [Yy][Ee][Ss]) if [ -n "${natd_interface}" ]; then ${fwcmd} add divert natd all from any to any via ${natd_interface} fi ;; esac # Stop RFC1918 nets on the outside interface ${fwcmd} add deny all from 10.0.0.0/8 to any via ${oif} ${fwcmd} add deny all from 172.16.0.0/12 to any via ${oif} ${fwcmd} add deny all from 192.168.0.0/16 to any via ${oif} # Stop draft-manning-dsua-03.txt (1 May 2000) nets (includes RESERVED-1, # DHCP auto-configuration, NET-TEST, MULTICAST (class D), and class E) # on the outside interface ${fwcmd} add deny all from 0.0.0.0/8 to any via ${oif} ${fwcmd} add deny all from 169.254.0.0/16 to any via ${oif} ${fwcmd} add deny all from 192.0.2.0/24 to any via ${oif} ${fwcmd} add deny all from 224.0.0.0/4 to any via ${oif} ${fwcmd} add deny all from 240.0.0.0/4 to any via ${oif} # Allow TCP through if setup succeeded ${fwcmd} add pass tcp from any to any established # Allow IP fragments to pass through ${fwcmd} add pass all from any to any frag # 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 ${fwcmd} add pass udp from any to ${oip} 53 ${fwcmd} add pass udp from ${oip} 53 to any # +++ neu! ${fwcmd} add pass tcp from any to ${iip} 53 setup ${fwcmd} add pass udp from any to ${iip} 53 ${fwcmd} add pass udp from ${iip} 53 to any ${fwcmd} add pass tcp from any to ${wiip} 53 setup ${fwcmd} add pass udp from any to ${wiip} 53 ${fwcmd} add pass udp from ${wiip} 53 to any # --- ${fwcmd} add pass tcp from 133.227.4.12 to ${oip} 22 ${fwcmd} add pass tcp from 133.227.7.0/24 to ${oip} 22 ${fwcmd} add pass tcp from 133.227.8.0/24 to ${oip} 22 ${fwcmd} add pass tcp from 61.172.141.65 to ${oip} 22 ${fwcmd} add allow icmp from any to any icmptype 0,3,8,11,12 # Allow access to our WWW ${fwcmd} add pass tcp from any to ${oip} 80,443 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 ${oip} to any 53 keep-state # Allow NTP queries out in the world ${fwcmd} add pass udp from ${oip} to any 123 keep-state # Everything else is denied by default, unless the # IPFIREWALL_DEFAULT_TO_ACCEPT option is set in your kernel # config file. ;; -- Chris Christoph P. U. Kukulies kuku_at_kukulies.org
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