Пример использования ipfw
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[править] NAT
Дано:
Внутренняя подсеть: 192.168.0.0/24
Интерфейс во внутреннюю подсеть: em1
Внешний адрес: 192.168.1.2
Интерфейс во внешнюю сеть: em0
Внутренний WWW сервер: 192.168.0.2
Необходимо:
Добавить в ядро опции:
# Firewall options IPFIREWALL # Firewall options IPFIREWALL_FORWARD options IPFIREWALL_VERBOSE options IPDIVERT options DUMMYNET # Firewall NAT options IPFIREWALL_NAT options LIBALIAS
Использовать следующими командами
# ipfw nat 1 config ip 192.168.1.2 redirect_port tcp 192.168.0.2:80 80 # ipfw add nat 1 ip from 192.168.0.0/24 to any out via em0 # ipfw add nat 1 ip from any to 192.168.1.2 in via em0
[править] Загрузочный скрипт
# Firewall firewall_enable="YES" firewall_type="SERVER" firewall_server_iif="em1" firewall_server_inet="192.168.0.0/24" firewall_server_oif="em0" firewall_server_onet="192.168.1.0/24" # NAT firewall_nat_enable="YES" firewall_nat_interface="em0" firewall_nat_address="192.168.1.2"
#!/bin/sh -
#
# Setup system for ipfw(4) firewall service.
#
# Suck in the configuration variables.
if [ -z "${source_rc_confs_defined}" ]; then
if [ -r /etc/defaults/rc.conf ]; then
. /etc/defaults/rc.conf
source_rc_confs
elif [ -r /etc/rc.conf ]; then
. /etc/rc.conf
fi
fi
############
# Define the firewall type in /etc/rc.conf. Valid values are:
# open - will allow anyone in
# server - 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 ``server the entries below should be customized
# appropriately.
setup_loopback () {
############
# 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
${fwcmd} add 300 deny ip from 127.0.0.0/8 to any
}
if [ -n "${1}" ]; then
firewall_type="${1}"
fi
. /etc/rc.subr
. /etc/network.subr
afexists inet6
ipv6_available=$?
############
# Set quiet mode if requested
#
case ${firewall_quiet} in
[Yy][Ee][Ss])
fwcmd="/sbin/ipfw -q"
;;
*)
fwcmd="/sbin/ipfw"
;;
esac
############
# Flush out the list before we begin.
#
${fwcmd} -f flush
setup_loopback
setup_ipv6_mandatory
############
# Network Address Translation. All packets are passed to natd(8)
# before they encounter your remaining rules. The firewall rules
# will then be run again on each packet after translation by natd
# starting at the rule number following the divert rule.
#
# For ``server firewall type the divert rule should be put to a
# different place to not interfere with address-checking rules.
#
case ${firewall_type} in
[Oo][Pp][Ee][Nn])
case ${firewall_nat_enable} in
[Yy][Ee][Ss])
if [ -n "${firewall_nat_interface}" ]; then
if echo "${firewall_nat_interface}" | \
grep -q -E '^[0-9]+(\.[0-9]+){0,3}$'; then
firewall_nat_flags="ip ${firewall_nat_interface} ${firewall_nat_flags}"
else
firewall_nat_flags="if ${firewall_nat_interface} ${firewall_nat_flags}"
fi
${fwcmd} nat 123 config log ${firewall_nat_flags}
${fwcmd} add 50 nat 123 ip4 from any to any via ${firewall_nat_interface}
fi
;;
esac
esac
############
# 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.
#
# ${fwcmd} add 65000 pass all from any to any
# Prototype setups.
#
case ${firewall_type} in
[Oo][Pp][Ee][Nn])
${fwcmd} add 65000 pass all from any to any
;;
[Ss][Ee][Rr][Vv][Ee][Rr])
############
# Configuration:
# firewall_server_iif: Inside IPv4 network interface.
# firewall_server_inet: Inside IPv4 network address.
# firewall_server_oif: Outside IPv4 network interface.
# firewall_server_onet: Outside IPv4 network address.
# firewall_nat_interface: NAT interface
# firewall_nat_address: NAT address
# firewall_vpn_net: VPN IPv4 network
# firewall_vpn_gateway: VPN IPv4 gateway
############
# set these to your outside interface network
oif="$firewall_server_oif"
onet="$firewall_server_onet"
# set these to your inside interface network
iif="$firewall_server_iif"
inet="$firewall_server_inet"
# set this VPN variable
vpn_net="${firewall_vpn_net}"
vpn_gateway="${firewall_vpn_gateway}"
# Stop spoofing
${fwcmd} add deny all from ${inet} to any in via ${oif}
${fwcmd} add deny all from ${onet} to any in via ${iif}
# BruteBlock
${fwcmd} add deny ip from table\(1\) to any
# Block bad gay's
${fwcmd} add deny ip from table\(2\) to any
# Stop standart ports
${fwcmd} add deny tcp from any to me 137,138,139,445,3127,3128,3306 via ${oif}
${fwcmd} add deny udp from any to me 67,68,137,138,139,145,389,445,631,3128,3306 via ${oif}
# 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}
# Squid
case ${squid_enable} in
[Yy][Ee][Ss])
${fwcmd} add fwd 127.0.0.1,3128 tcp from ${inet} to any 80 via ${iif}
;;
esac
case ${firewall_nat_enable} in
[Yy][Ee][Ss])
${fwcmd} nat 1 config ip ${firewall_nat_address}
${fwcmd} add nat 1 ip from ${inet} to any out via ${firewall_nat_interface}
${fwcmd} add nat 1 ip from any to ${firewall_nat_address} in via ${firewall_nat_interface}
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 ${oif}
# GRE
#${fwcmd} add allow tcp from any to me 1723
#${fwcmd} add allow gre from any to any
#${fwcmd} add allow ip from any to any via tun0
# 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 me smtp,pop3,smtps,pop3s setup
# Allow access to our DNS
${fwcmd} add pass tcp from any to me domain setup
${fwcmd} add pass udp from any to me domain
${fwcmd} add pass udp from me domain to any
# Allow access to our WWW
${fwcmd} add pass tcp from any to me http,https setup
# Allow SSH
${fwcmd} add pass tcp from any to me ssh setup
# Reject&Log all setup of incoming connections from the outside
${fwcmd} add deny log ip4 from any to any in via ${oif} setup proto tcp
# 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 me to any domain keep-state
# Allow NTP queries out in the world
${fwcmd} add pass udp from me to any ntp keep-state
# Allow ICMP
${fwcmd} add pass icmp from any to any
# Allow UDP
${fwcmd} add pass udp from any to any
# BadGuys
/etc/badguys.sh
;;
[Cc][Ll][Oo][Ss][Ee][Dd])
${fwcmd} add 65000 deny ip from any to any
;;
[Uu][Nn][Kk][Nn][Oo][Ww][Nn])
;;
*)
if [ -r "${firewall_type}" ]; then
${fwcmd} ${firewall_flags} ${firewall_type}
fi
;;
esac
