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IPFW [58]

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Балансировка соединений во FreeBSD через два линка
Конфигурация:

   * FreeBSD 5.4 - Stable
   * ipfw, natd, natd2, ng_one2many, squid, jftpgw.
   * 2 внешних DSL линка.
   * 3 сетевые карты ( 2 линка и 1 - локальная сеть)

   Метод: natd запускаем с параметром alias_address для привязки к каждому из двух внешних IP, далее используем ipfw prob для задания вероятности перехода на другое ipfw правило  и форвадим в нужный интерфейс через ipfw fwd

   Первый, заведомо неработающий, вариант:
  
           route add default $ext_gw1
           .....
           ipfw add allow ip from any to any via $int_if

           ipfw add divert natd1 ip from any to $ext_ip1 in
           ipfw add divert natd2 ip from any to $ext_ip2 in

           # Простой вариант: 50% обрабатываем правилом 8100 и 50% - правилом 8500
           ipfw add skipto 8000 ip from $lan to any out
           ipfw add allow ip from any to $lan in

           ipfw add 8000 prob 0.5 skipto 8500 ip from any to any out
           ipfw add 8100 divert natd1 ip from any to any out
           ipfw add 8200 allow ip from $ext_ip1 to any out
           ipfw add 8500 divert natd2 ip from any to any out
           ipfw add 8600 fwd $ext_gw2 ip from $ext_ip2 to any out

           ipfw add deny ip from any to any out

   Две причины по которым данная схема оказывается неработоспособной:
   1. Пакеты уходящие через ext_gw2, после компанды ipfw fwd, могут вернуться не через заданный интерфейс, они придут через default route.
   2. Для TCP соединений вероятностная балансировка пакетов без учета сессий не приведет ни к чему хорошему.

   Рабочее решение:
   Файл rc.conf:

           hostname="fw.xx.yy.zz"
           # Внутрянняя локальная сеть
           ifconfig_vr0="inet 192.168.1.1 netmask 255.255.255.0"
           # Внешние линки
           ifconfig_rl0="inet 192.168.8.70 netmask 255.255.255.0"
           ifconfig_rl0_alias0="inet 192.168.0.99 netmask 255.255.255.0"
           defaultrouter="192.168.8.1"

           # Включение фаервола
           gateway_enable="YES"
           firewall_enable="YES"
           firewall_script="/etc/ipfw.rules"
           firewall_logging="YES"

           # Включение NAT для двух внешних IP
           natd_enable="YES"
           natd_flags="-f /etc/natd1.conf"
           # Не забудьте указать порт natd2 в /etc/services
           # Проще всего на основе /etc/rc.d/natd создать /usr/local/etc/rc.d/natd2.sh

           natd2_enable="YES"
           natd2_flags="-f /etc/natd2.conf"

           #Enable the proxy server
           squid_enable="YES"

           # Sync server time from internet
           ntpd_enable="YES"
           ntpd_flags="-c /etc/ntp.conf"

           # Bandwidth monitoring with html graphs
           bandwidthd_enable="YES"

           # jftpgw ftp proxy for anonymous ftp proxy-cache
           jftpgw_enable="YES"

           # Load the script to hook the two external nic's together
           # Add the actual script file to /usr/local/etc/rc.d/netmon1.sh
           netmon1_enable="YES"

   Вместо ipfw fwd будем использовать netgraph модуль ng_one2many

   Рабочий скрипт:

           #!/bin/sh
           # Load the kernel modules
           kldload ng_ether
           kldload ng_one2many

           ifconfig rl0 down
           ifconfig rl1 down
           # Plumb nodes together
           ngctl mkpeer rl0: one2many upper one
           ngctl connect rl0: rl0:upper lower many0
           ngctl connect rl1: rl0:upper lower many1

           # Allow rl1 to xmit / recv rl0 frames
           ifconfig rl1 promisc
           ngctl msg rl1: setautosrc 0
           # Configure to transmit to all interfaces
           ngctl  msg rl0:upper setconfig "{xmitAlg=2 failAlg=1 enabledLinks =[ 1 1 ] }"

           echo "Now up the interfaces again"
           ifconfig rl0 up
           ifconfig rl1 up
           ifconfig rl0 inet 192.168.8.70 netmask 255.255.255.0
           ifconfig rl0 inet 192.168.0.99 netmask 255.255.255.0 alias
           Make sure the default route is correct.
           route delete default
           route add default 192.168.0.1
           echo "Done"

   Правила ipfw:

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

           # Set rules command prefix
           cmd="ipfw -q add"
           bwm="ipfw -q pipe"
           skip="skipto 8000"
           ext_if1="rl0"         # public interface name of NIC
           ext_if2="rl0"
           lan="192.168.1.0/24"
           int_if="vr0"    # private interface name of NIC
           ext_ip1="192.168.8.70"
           ext_ip2="192.168.0.99"
           ext_gw1="192.168.8.1"
           ext_gw2="192.168.0.1"

           # Setup the different Sets to be used for different connection options
           ipfw -q set disable 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
           # Initially enable set 1 and 2 and 12 assuming we have 2 WAN links up and working
           ipfw -q set enable 1 2 12

           # Specify which ip addresses get what bandwidth
           # Can also tell this dhcp server to give certain addresses to selected mac
           # addresses in file /usr/local/etc/dhcpd.conf
           u512k=""      # Users given 512kb/s link
           u256k="192.168.1.0/24{2-254}"         # Users given 256kb/s link
           u128k=""         # Users given 128kb/s link
           u64k=""         # Users given 64kb/s link
           #  squid  and  jftpgw  have to be configured seperately to provide the same
           #   bandwidth  management  as  what  is  configured  here.  See  their config/man  pages.

           # Check and drop packets that are appearing to come from
           # the destination LAN i.e. a spoofed source ip address
           $cmd deny ip from any to any not antispoof in

           # No restrictions on Loopback Interface
           # Protect spoofing to localhost
           $cmd allow ip from any to any via lo0
           $cmd deny ip from any to 127.0.0.0/8
           $cmd deny ip from 127.0.0.0/8 to any

           # check if packet is inbound and nat address if it is
           $cmd 1000 divert natd1 ip from any to $ext_ip1 in
           $cmd 1000 divert natd2 ip from any to $ext_ip2 in

           # Divert incoming http and ftp traffic to the proxy (squid and jftpgw)
           $cmd fwd 192.168.1.1,3128 tcp from $lan to any 80 in via $int_if
           $cmd fwd 192.168.1.1,2370 tcp from $lan to any 21 via $int_if

           # Allow the rest of the LAN traffic in and out
           $cmd allow ip from any to any via $int_if

           ################ Bandwidth Management ################
           # Setup up pipes for each of the user groups

           # Users with 512Kb / 256Kb access (in / out)
           $cmd pipe 10 ip from any to $u512k in via $ext_if1
           $cmd pipe 11 ip from $u512k to any out via $ext_if1
           $bwm 10 config mask dst-ip 0x000000ff bw 512Kbit/s queue 4KBytes
           $bwm 11 config mask src-ip 0x000000ff bw 256Kbit/s queue 3KBytes

           # Users with 256Kb / 128Kb access
           $cmd pipe 20 ip from any to $u256k in via $ext_if1
           $cmd pipe 21 ip from $u256k to any out via $ext_if1
           $bwm 20 config mask dst-ip 0x000000ff bw 256Kbit/s queue 4KBytes
           $bwm 21 config mask src-ip 0x000000ff bw 128Kbit/s queue 3KBytes

           # Users with 128Kb / 64Kb access
           $cmd pipe 30 ip from any to $u128k in via $ext_if1
           $cmd pipe 31 ip from $u128k to any out via $ext_if1
           $bwm 30 config mask dst-ip 0x000000ff bw 128Kbit/s queue 4KBytes
           $bwm 31 config mask src-ip 0x000000ff bw 64Kbit/s queue 3KBytes

           # Users with 64Kb / 56Kb access
           $cmd pipe 40 ip from any to $u64k in via $ext_if1
           $cmd pipe 41 ip from $u64k to any out via $ext_if1
           $bwm 40 config mask dst-ip 0x000000ff bw 64Kbit/s queue 3KBytes
           $bwm 41 config mask src-ip 0x000000ff bw 56Kbit/s queue 2KBytes

           #####################################################
           # Interface facing Public Internet (Outbound Section)

           # Allow out access to my ISP's Domain name server.
           # Get the IP addresses from /etc/resolv.conf file
           #$cmd   $skip  UDP  from  any  to  {  196.7.0.138  or  196.28.86.2  or 196.28.86.3
           or 196.25.1.1 } 53 out
           $cmd $skip UDP from any to any 53 out

           # Allow this box out access to my ISP's DHCP server (or adsl router)
           $cmd $skip udp from me to any 67 out

           # Allow skype connections out
           # Allow ntp time server out
           $cmd $skip UDP from any to any 80,443,123,1024-65535 out
           $cmd $skip UDP from any 80,443,1024-65535 to any out
           $cmd $skip tcp from any 1024-65535 to any 1024-65535 out

           # Allow out non-secure standard www function - via proxy
           $cmd $skip tcp from me to any 80

           # Allow out secure www function https over TLS SSL
           # Allow out send & get email function (GMail uses ports 587, 995)
           # Allow out MSN messenger
           # Allow out Time, nntp news (i.e. news groups),
           # SSH (secure FTP, Telnet, and SCP), whois
           $cmd  $skip  tcp  from any to any 443,25,110,587,995,1863,37,119,22,43 out

           # Allow out regular http and ftp access (for if proxy and fwd cmd's above are off)
           $cmd $skip tcp from $lan 1024-65535 to any 20,21,80 out

           # Allow out ping
           $cmd $skip icmp from $lan to any out icmptypes 8
           $cmd allow icmp from me to 192.168.0.0/16 out icmptypes 8
           $cmd allow icmp from $ext_ip1,$ext_ip2 to any out icmptypes 8

           # Allow www and ftp proxy out
           $cmd $skip tcp from me to any 20,21,80 out uid squid

           # Allow out FreeBSD (make install & CVSUP) functions
           # Give user root "GOD" privileges.
           $cmd allow ip from me to any out uid root

           # Deny the rest out
           $cmd deny log ip from any to any out

           #######################################################
           # Interface facing Public Internet (Inbound Section)
           # Interrogate packets originating from the public Internet
           # destine for this gateway server or the private network.

           # Deny all inbound traffic from non-routable reserved address spaces
           #$cmd 300 deny all from 192.168.0.0/16  to any in via $ext_if1  #RFC 1918 private IP
           $cmd deny all from 172.16.0.0/12,10.0.0.0/8,0.0.0.0/8,169.254.0.0/16,192.0.2.0/24,204.152.64.0/23,224.0.0.0/3 to any in
           #RFC 1918 private IP #DHCP auto-config #reserved for docs #Sun cluster
           #Class D & E multicast

           # Deny ident
           # Deny all Netbios service. 137=name, 138=datagram, 139=session
           # Netbios is MS/Windows sharing services.
           # Block MS/Windows hosts2 name server requests 81
           $cmd deny all from any to any 113,137,138,139,81 in

           # Allow traffic in from ISP's DHCP server. This rule must contain
           # the IP address of your ISP's DHCP server as it's the only
           # authorized source to send this packet type.
           $cmd allow udp from 192.168.8.1,192.168.0.1 to any 68,5678 in

           # Allow dns lookups back in
           $cmd allow udp from any 53,67 to $lan in
           $cmd allow udp from any 53,67 to me in

           # Allow skype connections in
           $cmd allow udp from any 80,123,443,1024-655353 to $lan in
           $cmd allow udp from any to $lan 80,443,1024-655353 in
           $cmd deny log udp from any to any in # Deny the rest
           $cmd allow tcp from any 1024-65535 to $lan 1024-65535 in

           # Allow in SecureFTP and SSH from public Internet
           $cmd allow tcp from { 192.168.0.0/24 or $lan or 192.168.8.0/24 } to me 22 in  #setup limit src-addr 3
           $cmd allow tcp from any to me 22 in setup limit src-addr 1

           # Allow in standard www function because I have Apache server - or is there an internal webserver?
           # Allow Webmin connections from close-by
           $cmd  allow  tcp  from  {  192.168.8.0/24  or  192.168.0.0/24  } to me 80,10000 in
           $cmd allow tcp from any to $lan 80,10000 in

           # Allow outgoing web traffic (via proxy) back in
           $cmd allow tcp from any 20,21,80 to me 1024-65535 in

           # Deny the rest to me
           $cmd deny log tcp from any to me in

           # Allow out regular ftp, http access if proxy is off
           $cmd allow tcp from any 20,21,80 to $lan 1024-65535 in

           # Allow in secure www function https over TLS SSL
           # Allow in send & get email function (GMail uses ports 587, 995)
           # Allow in MSN messenger
           # Allow in Time, nntp news (i.e. news groups),
           # SSH (secure FTP, Telnet, and SCP), whois
           $cmd allow tcp from any 443,25,110,587,995,1863,37,119,22,43 to any in

           #Allow in ICMP (ping) from public networks close by only.
           $cmd allow icmp from 192.168.0.0/16 to me in icmptypes 0,3,11
           $cmd allow icmp from any to $lan in icmptypes 0,3,11
           #  Used for testing network connections
           $cmd allow icmp from 196.7.0.138,196.25.1.1,196.4.160.7 to me in icmptypes 0,3,11

           #Deny the rest
           $cmd deny icmp from any to any in

           # Reject & Log all unauthorized incoming connections from the public Internet (/var/log/security)
           $cmd deny log all from any to any in

           # This is skipto location for outbound stateful rules
           $cmd 8000 skipto 9000 tcp from any to any out setup
           $cmd 8010 skipto 9000 udp from any to any out
           $cmd 8020 skipto 9000 icmp from any to any out
           $cmd 8100 tee natd1 ip from any to any out
           $cmd 8150 check-state
           $cmd 8200 divert natd2 ip from any to any out
           $cmd 8250 check-state
           $cmd 8400 deny ip from any to any out
           $cmd 9000 set 12 prob 0.5 skipto 9500 ip from any to any out
           $cmd 9100 set 1 divert natd1 ip from any to any out
           $cmd 9200 set 1 allow ip from any to any out keep-state
           $cmd 9500 set 2 divert natd2 ip from any to any out
           $cmd 9600 set 2 allow ip from any to any out keep-state

           # deny and log all packets that fell through to see what they are
           $cmd 9999 deny log all from any to any

   Скрипт для обеспечания отказоустойчивости, на случай падения одного из линков

           #!/bin/sh
           target="196.7.0.138"
           ext_gw1="192.168.8.1"
           ext_gw2="192.168.0.1"

           # Setup route to ping through
           route -q add -host $target $ext_gw1
           # Test link one through ext_gw1 to see if any packets get returned
           ping1=$( ping -q -c 3 -f -s 8 -o -t 2 196.7.0.138 | grep "packet loss" | cut -c24-24 )
           # Test link two through ext_gw2 to see if any packets get returned
           route -q delete $target
           route -q add -host $target $ext_gw2
           ping2=$( ping -q -c 3 -f -s 8 -o -t 2 196.7.0.138 | grep "packet loss" | cut -c24-24 )
           # Remove route
           route -q delete $target

           # Configure the ipfw sets as per network route availability
           if [ "$ping1" != "0" ]; then
               if [ "$ping2" = "1" ]; then
               ipfw set enable 1 2 12
               else
               ipfw set enable 1
               ipfw set disable 2 12
               fi
           else
               if [ "$ping2" != "0" ]; then
                   ipfw set disable 1 12
               ipfw set enable 2
               else
               # echo "enabling everything to wait for network recovery"
               ipfw set enable 1 2 12
               fi
           fi

Источник: http://www.opennet.ru/base/net/2link_balance2.txt.html
Категория: IPFW | Добавил: oleg (28.12.2007) | Автор: G Bryant
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