第 33 章. 防火墙

pf_flags=""                     # additional flags for pfctl startup

pf_rules="/path/to/pf.conf"

pflog_logfile="/var/log/pflog"  # where pflogd should store the logfile
pflog_flags=""                  # additional flags for pflogd startup

gateway_enable="YES"            # Enable as LAN gateway

block in all
pass out all keep state

tcp_services = "{ ssh, smtp, domain, www, pop3, auth, pop3s }"
udp_services = "{ domain }"

tcp_services = "{ ssh, smtp, domain, www, pop3, auth, pop3s }"
udp_services = "{ domain }"
block all
pass out proto tcp to any port $tcp_services keep state
pass proto udp to any port $udp_services keep state

options         ALTQ
options         ALTQ_CBQ        # Class Based Queuing (CBQ)
options         ALTQ_RED        # Random Early Detection (RED)
options         ALTQ_RIO        # RED In/Out
options         ALTQ_HFSC       # Hierarchical Packet Scheduler (HFSC)
options         ALTQ_PRIQ       # Priority Queuing (PRIQ)

#!/bin/sh
# Flush out the list before we begin.
ipfw -q -f flush

# Set rules command prefix
cmd="ipfw -q add"
pif="dc0"     # interface name of NIC attached to Internet

# Change xl0 to LAN NIC interface name
$cmd 00005 allow all from any to any via xl0

# No restrictions on Loopback Interface
$cmd 00010 allow all from any to any via lo0

$cmd 00101 check-state

# Allow access to public DNS
# Replace x.x.x.x with the IP address of a public DNS server
# and repeat for each DNS server in /etc/resolv.conf
$cmd 00110 allow tcp from any to x.x.x.x 53 out via $pif setup keep-state
$cmd 00111 allow udp from any to x.x.x.x 53 out via $pif keep-state

# Allow access to ISP's DHCP server for cable/DSL configurations.
# Use the first rule and check log for IP address.
# Then, uncomment the second rule, input the IP address, and delete the first rule
$cmd 00120 allow log udp from any to any 67 out via $pif keep-state
#$cmd 00120 allow udp from any to x.x.x.x 67 out via $pif keep-state

# Allow outbound HTTP and HTTPS connections
$cmd 00200 allow tcp from any to any 80 out via $pif setup keep-state
$cmd 00220 allow tcp from any to any 443 out via $pif setup keep-state

# Allow outbound email connections
$cmd 00230 allow tcp from any to any 25 out via $pif setup keep-state
$cmd 00231 allow tcp from any to any 110 out via $pif setup keep-state

# Allow outbound ping
$cmd 00250 allow icmp from any to any out via $pif keep-state

# Allow outbound NTP
$cmd 00260 allow udp from any to any 123 out via $pif keep-state

# Allow outbound SSH
$cmd 00280 allow tcp from any to any 22 out via $pif setup keep-state

# deny and log all other outbound connections
$cmd 00299 deny log all from any to any out via $pif

# Deny all inbound traffic from non-routable reserved address spaces
$cmd 00300 deny all from 192.168.0.0/16 to any in via $pif     #RFC 1918 private IP
$cmd 00301 deny all from 172.16.0.0/12 to any in via $pif      #RFC 1918 private IP
$cmd 00302 deny all from 10.0.0.0/8 to any in via $pif         #RFC 1918 private IP
$cmd 00303 deny all from 127.0.0.0/8 to any in via $pif        #loopback
$cmd 00304 deny all from 0.0.0.0/8 to any in via $pif          #loopback
$cmd 00305 deny all from 169.254.0.0/16 to any in via $pif     #DHCP auto-config
$cmd 00306 deny all from 192.0.2.0/24 to any in via $pif       #reserved for docs
$cmd 00307 deny all from 204.152.64.0/23 to any in via $pif    #Sun cluster interconnect
$cmd 00308 deny all from 224.0.0.0/3 to any in via $pif        #Class D & E multicast

# Deny public pings
$cmd 00310 deny icmp from any to any in via $pif

# Deny ident
$cmd 00315 deny tcp from any to any 113 in via $pif

# Deny all Netbios services.
$cmd 00320 deny tcp from any to any 137 in via $pif
$cmd 00321 deny tcp from any to any 138 in via $pif
$cmd 00322 deny tcp from any to any 139 in via $pif
$cmd 00323 deny tcp from any to any 81 in via $pif

# Deny fragments
$cmd 00330 deny all from any to any frag in via $pif

# Deny ACK packets that did not match the dynamic rule table
$cmd 00332 deny tcp from any to any established in via $pif

# Allow traffic from ISP's DHCP server.
# Replace x.x.x.x with the same IP address used in rule 00120.
#$cmd 00360 allow udp from any to x.x.x.x 67 in via $pif keep-state

# Allow HTTP connections to internal web server
$cmd 00400 allow tcp from any to me 80 in via $pif setup limit src-addr 2

# Allow inbound SSH connections
$cmd 00410 allow tcp from any to me 22 in via $pif setup limit src-addr 2

# Reject and log all other incoming connections
$cmd 00499 deny log all from any to any in via $pif

# Everything else is denied and logged
$cmd 00999 deny log all from any to any

gateway_enable="YES"
firewall_enable="YES"
firewall_nat_enable="YES"

#!/bin/sh
ipfw -q -f flush
cmd="ipfw -q add"
skip="skipto 1000"
pif=dc0
ks="keep-state"
good_tcpo="22,25,37,53,80,443,110"

net.inet.tcp.tso="0"

ipfw disable one_pass
ipfw -q nat 1 config if $pif same_ports unreg_only reset

$cmd 005 allow all from any to any via xl0  # exclude LAN traffic
$cmd 010 allow all from any to any via lo0  # exclude loopback traffic
$cmd 099 reass all from any to any in       # reassemble inbound packets
$cmd 100 nat 1 ip from any to any in via $pif # NAT any inbound packets
# Allow the packet through if it has an existing entry in the dynamic rules table
$cmd 101 check-state

# Authorized outbound packets
$cmd 120 $skip udp from any to x.x.x.x 53 out via $pif $ks
$cmd 121 $skip udp from any to x.x.x.x 67 out via $pif $ks
$cmd 125 $skip tcp from any to any $good_tcpo out via $pif setup $ks
$cmd 130 $skip icmp from any to any out via $pif $ks

$cmd 999 deny log all from any to any
$cmd 1000 nat 1 ip from any to any out via $pif # skipto location for outbound stateful rules
$cmd 1001 allow ip from any to any

options    IPFIREWALL			# enables IPFW
options    IPFIREWALL_VERBOSE		# enables logging for rules with log keyword to syslogd(8)
options    IPFIREWALL_VERBOSE_LIMIT=5	# limits number of logged packets per-entry
options    IPFIREWALL_DEFAULT_TO_ACCEPT # sets default policy to pass what is not explicitly denied
options    IPFIREWALL_NAT		# enables basic in-kernel NAT support
options    LIBALIAS			# enables full in-kernel NAT support
options    IPFIREWALL_NAT64		# enables in-kernel NAT64 support
options    IPFIREWALL_NPTV6		# enables in-kernel IPv6 NPT support
options    IPFIREWALL_PMOD		# enables protocols modification module support
options    IPDIVERT			# enables NAT through natd(8)

options IPFILTER
options IPFILTER_LOG
options IPFILTER_LOOKUP
options IPFILTER_DEFAULT_BLOCK

ipfilter_enable="YES"             # Start ipf firewall
ipfilter_rules="/etc/ipf.rules"   # loads rules definition text file
ipv6_ipfilter_rules="/etc/ipf6.rules" # loads rules definition text file for IPv6
ipmon_enable="YES"                # Start IP monitor log
ipmon_flags="-Ds"                 # D = start as daemon
                                  # s = log to syslog
                                  # v = log tcp window, ack, seq
                                  # n = map IP & port to names

gateway_enable="YES"              # Enable as LAN gateway
ipnat_enable="YES"                # Start ipnat function
ipnat_rules="/etc/ipnat.rules"    # rules definition file for ipnat

#  service ipfilter start

# no restrictions on loopback interface
pass in quick on lo0 all
pass out quick on lo0 all

# no restrictions on inside LAN interface for private network
pass out quick on xl0 all
pass in quick on xl0 all

# interface facing Internet (outbound)
# Matches session start requests originating from or behind the
# firewall, destined for the Internet.

# Allow outbound access to public DNS servers.
# Replace x.x.x.x with address listed in /etc/resolv.conf.
# Repeat for each DNS server.
pass out quick on dc0 proto tcp from any to x.x.x.x port = 53 flags S keep state
pass out quick on dc0 proto udp from any to x.x.x.x port = 53 keep state

# Allow access to ISP's specified DHCP server for cable or DSL networks.
# Use the first rule, then check log for the IP address of DHCP server.
# Then, uncomment the second rule, replace z.z.z.z with the IP address,
# and comment out the first rule
pass out log quick on dc0 proto udp from any to any port = 67 keep state
#pass out quick on dc0 proto udp from any to z.z.z.z port = 67 keep state

# Allow HTTP and HTTPS
pass out quick on dc0 proto tcp from any to any port = 80 flags S keep state
pass out quick on dc0 proto tcp from any to any port = 443 flags S keep state

# Allow email
pass out quick on dc0 proto tcp from any to any port = 110 flags S keep state
pass out quick on dc0 proto tcp from any to any port = 25 flags S keep state

# Allow NTP
pass out quick on dc0 proto tcp from any to any port = 37 flags S keep state

# Allow FTP
pass out quick on dc0 proto tcp from any to any port = 21 flags S keep state

# Allow SSH
pass out quick on dc0 proto tcp from any to any port = 22 flags S keep state

# Allow ping
pass out quick on dc0 proto icmp from any to any icmp-type 8 keep state

# Block and log everything else
block out log first quick on dc0 all

# interface facing Internet (inbound)
# Block all inbound traffic from non-routable or reserved address spaces
block in quick on dc0 from 192.168.0.0/16 to any    #RFC 1918 private IP
block in quick on dc0 from 172.16.0.0/12 to any     #RFC 1918 private IP
block in quick on dc0 from 10.0.0.0/8 to any        #RFC 1918 private IP
block in quick on dc0 from 127.0.0.0/8 to any       #loopback
block in quick on dc0 from 0.0.0.0/8 to any         #loopback
block in quick on dc0 from 169.254.0.0/16 to any    #DHCP auto-config
block in quick on dc0 from 192.0.2.0/24 to any      #reserved for docs
block in quick on dc0 from 204.152.64.0/23 to any   #Sun cluster interconnect
block in quick on dc0 from 224.0.0.0/3 to any       #Class D & E multicast

# Block fragments and too short tcp packets
block in quick on dc0 all with frags
block in quick on dc0 proto tcp all with short

# block source routed packets
block in quick on dc0 all with opt lsrr
block in quick on dc0 all with opt ssrr

# Block OS fingerprint attempts and log first occurrence
block in log first quick on dc0 proto tcp from any to any flags FUP

# Block anything with special options
block in quick on dc0 all with ipopts

# Block public pings and ident
block in quick on dc0 proto icmp all icmp-type 8
block in quick on dc0 proto tcp from any to any port = 113

# Block incoming Netbios services
block in log first quick on dc0 proto tcp/udp from any to any port = 137
block in log first quick on dc0 proto tcp/udp from any to any port = 138
block in log first quick on dc0 proto tcp/udp from any to any port = 139
block in log first quick on dc0 proto tcp/udp from any to any port = 81

# Allow traffic in from ISP's DHCP server. Replace z.z.z.z with
# the same IP address used in the outbound section.
pass in quick on dc0 proto udp from z.z.z.z to any port = 68 keep state

# Allow public connections to specified internal web server
pass in quick on dc0 proto tcp from any to x.x.x.x port = 80 flags S keep state

# Block and log only first occurrence of all remaining traffic.
block in log first quick on dc0 all

gateway_enable="YES"
ipnat_enable="YES"
ipnat_rules="/etc/ipnat.rules"

map IF LAN_IP_RANGE -> PUBLIC_ADDRESS

map dc0 192.168.1.0/24 -> 0/32 portmap tcp/udp 20000:60000

map dc0 192.168.1.0/24 -> 0/32 portmap tcp/udp auto

map dc0 192.168.1.0/24 -> 204.134.75.0/255.255.255.0
map dc0 192.168.1.0/24 -> 204.134.75.0/24

rdr dc0 20.20.20.5/32 port 80 -> 10.0.10.25 port 80

rdr dc0 0.0.0.0/0 port 80 -> 10.0.10.25 port 80

map dc0 10.0.10.0/29 -> 0/32 proxy port 21 ftp/tcp
map dc0 0.0.0.0/0 -> 0/32 proxy port 21 ftp/tcp
map dc0 10.0.10.0/29 -> 0/32

# Allow out LAN PC client FTP to public Internet
# Active and passive modes
pass out quick on rl0 proto tcp from any to any port = 21 flags S keep state

# Allow out passive mode data channel high order port numbers
pass out quick on rl0 proto tcp from any to any port > 1024 flags S keep state

# Active mode let data channel in from FTP server
pass in quick on rl0 proto tcp from any to any port = 20 flags S keep state

ipmon_flags="-Ds" # D = start as daemon
                  # s = log to syslog
                  # v = log tcp window, ack, seq
                  # n = map IP & port to names

local0.* /var/log/ipfilter.log

UseBlacklist yes

ftpd_flags="-B"