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½ñÌì¸ø´ó¼Ò½«iptables£¬¼´linuxϵķÀ»ðǽ


1. °²×°ÎÒ²»½²ÁË£¬RH9µÄrpm°²×°·½Ê½·Ç³£¼òµ¥£¬´ó¼ÒÖ»ÒªÔÚrhµÄ°²×°Ô´ÅÌÕÒµ½ÏàÓ¦µÄrpm°ü¾ÍÐС£

È»ºó rpm -Uvh iptables-?.i386.rpm


2. ÎÒÃǽñÌìµ÷ÊԵĻ·¾³ÊÇһ̨˫Íø¿¨µÄ·þÎñÆ÷£¬Í¨¹ýDDN¹Ì¶¨ipµØÖ·ÉÏÍø£¬Á½¿éÍø¿¨·Ö±ðÊÇ
eth0: 211.101.251.4 ÍⲿipµØÖ·£¬Ö±½ÓÉÏÍø
eth1: 192.168.0.1 ÄÚ²¿Íø¿¨µØÖ·£¬Á¬½Ó192.168.0.0/255.255.255.0Íø¶Ï¾ÖÓòÍø

3.¿Í»§¶ËAÊÇ̨WWW£¬µØÖ·ÊÇ192.168.0.2¡£ÎÒÃǽ«ÀûÓúóÃæµÄDNAT¹¦ÄÜ£¬ÈÃÍâÃæµÄ»úÆ÷ÄÜ·ÃÎÊÕą̂»úÆ÷µÄwww·þÎñ¡£ÆäËû¿Í»§¶Ë¶¼ÔÚ192.168.0.0/24Íø¶Î£¬ÇÒÍø¹Ø¶¼Ö¸Ïò192.168.0.1

4. Èç¹û´ó¼ÒҪʹÓÃiptablesµÄNAT¹¦ÄÜ£¬Ö®Ç°ÎÒÃÇҪȷ±£ÏµÍ³ÄÚºËÅäÖõÄÊÇÕýÈ·µÄ£¬ÎÒµÄiptablesºÃ¼¸´Î¾ÍÒòΪÄں˱àÒë´íÎó£¬Ôì³É¿Í»§¶Ë²»ÄÜÕý³£Ê¹ÓÃSNAT¹¦ÄÜ£¬ÉõÖÁ²»ÄܼÓÔØip_tablesÄ£¿é¡£ÕâÊÇÒ»°ãµÄÄÚºËÅäÖ㬻ù±¾ÉÏiptablesµÄNAT¹¦ÄÜÄÜÕý³£Ê¹Óã¬Äں˰汾²»Í¬¿ÉÄÜÏÔʾ²»Ò»Ñù£¬´ó¼ÒÁé»îÕÆÎÕ¾ÍÐУ¬Ó¦¸Ã²»»á³öÏÖÂé·³¡£


ÒýÓÃ:
Networking options --->
[*] Network packet filtering (replaces ipchains)
[*] TCP/IP networking
IP: Netfilter Configuration --->
Connection tracking (required for masq/NAT) (NEW)
FTP protocol support (NEW)
IP tables support (required for filtering/masq/NAT) (NEW)
limit match support (NEW)
MAC address match support (NEW)
netfilter MARK match support (NEW)
Multiple port match support (NEW)
TOS match support (NEW)
tcpmss match support (NEW)
Connection state match support (NEW)
Packet filtering (NEW)
REJECT target support (NEW)
Full NAT (NEW)
MASQUERADE target support (NEW)
REDIRECT target support (NEW)
Packet mangling (NEW)
TOS target support (NEW)
MARK target support (NEW)
LOG target support (NEW)
TCPMSS target support (NEW)
ipchains (2.2-style) support (NEW)
< > ipfwadm (2.0-style) support (NEW)



5. ÎÒÃÇÒª´ò¿ªip_forward,
Ö±½ÓÐÞ¸Ä/etc/sysctl.conf Õâ¸öÎĵµ£¬°Ñnet.ipv4.ip_forward= 1 ²¢°ÑÇ°ÃæµÄ#È¥µô£¬»òÕß
echo "1" > /proc/sys/net/ipv4/ip_forward £¬µ«ÊÇÏ´ÎÖØÆð»¹ÊDZä0£¬ËùÒÔ»¹ÊÇÖ±½ÓÐÞ¸ÄÎĵµµÄºÃ¡£

6. ÎÒÃÇÔÚʹÓÃiptables֮ǰ£¬ÏÈÒªÁ˽âiptablesµÄ²ÎÊý£º

ACCEPT
½ÓÊÜÕâ¸ö·â°ü£¬Ò²¾ÍÊÇ¿ÉÒÔͨ¹ý¹æÔò¼ìÑé¶ø·ÅÐС¢Ë³Àûͨ¹ýÕâ¸öÁ´¡£

DROP
¶ªÆúÕâ¸ö·â°ü£¬Ò²¾Í²»ÄÜͨ¹ý¹æÔò¼ìÑé¶ø±»µ²µô¡£

REJECT
Óë DROP Ò»Ñù£¬µ«»áÏòÀ´Ô´µØËͳö ICMP ·â°ü£¬¸æÖ®¶Ô·½¡® port unreachable ¡¯µÄ´íÎóÐÅÏ¢¡£

REDIRECT
½«·â°üÖص¼ÖÁ ±¾»ú¶Ë µÄÆäËü port ¡£

SNAT / DNAT / MASQUERADE
ÕâЩ¶¼ÊÇ NAT µÄ´¦Àí£¬ÊÓÒªÇó¶øÐÞ¸ÄΪÌض¨µÄ Source Socket »ò Destination Socket ¡¢»ò¶¯Ì¬µÄ¸ù¾Ý·ÓÉÅжÏááµÄ½çÃæ¶øÐÞ¸Ä Source Socket ¡£

½¨Á¢Ò»¸öеÄ(×Ô¶¨)Á´ ( -N )¡£
ɾ³ýÒ»¸ö¿ÕµÄ(×Ô¶¨)Á´ ( -X )¡£
¸Ä±äÒ»¸öÄÚ½¨Á´µÄÔ­Ôò ( -P )¡£
ÁгöÒ»¸öÁ´ÖеĹæÔò ( -L )¡£
Çå³ýÒ»¸ö(ÄÚ½¨)Á´ÖеÄËùÓйæÔò ( -F )¡£
ÔÚÒ»¸öÁ´µÄ×îááÃæÐÂÔö( append ) Ò»Ìõ¹æÔò ( -A )¡£
ÔÚÁ´ÄÚij¸öλÖòåÈë( insert ) Ò»ÌõйæÔò( -I )¡£
ÔÚÁ´ÄÚij¸öλÖÃÌæ»»( replace ) Ò»Ìõ¹æÔò ( -R )¡£
ÔÚÁ´ÄÚij¸öλÖÃɾ³ý( delete ) Ò»Ìõ¹æÔò ( -D )¡£
ɾ³ý(delete) Á´ÄÚµÚÒ»Ìõ·ûºÏµÄ¹æÔò (-D)¡£
ÔÚ iptables ÖУ¬ÒªÖ¸¶¨¹æÔòÊÇÓû×÷ÓÃÔÚÄÇÒ»¸ö¹æÔò±íÉÏ(ʹÓà -t À´Ö¸¶¨£¬Èç -t nat)£¬Èô²»Ö¸¶¨£¬ÔòÔ¤ÉèÊÇ×÷ÓÃÔÚ filter Õâ¸ö±í¡£


·â°üÓÚ·À»ðǽÖеÄÁ÷Ïò ( INPUT¡¢OUTPUT¡¢FORWARD )
Ïà¹Ø½çÃæ ( -i »ò -o )
ËùÊôЭ¶¨ ( -p )
Á¬ÏßÀàÐÍ ( -m state )
·â°üÀàÐÍ ( --syn )
À´Ô´µØ ( -s )
À´Ô´¶Ë¿Ú ( --sport )
Ä¿µÄµØ ( -d )
Ä¿µÄµØ¶Ë¿Ú ( --dport )


ºÃÁË£¬¿ªÊ¼¹¤×÷£¡

Ê×ÏȲ鿴һÏ»úÆ÷ÉϵÄÓйØÓÚiptablesµÄÉ趨Çé¿ö
×÷·¨ÈçÏ£º

iptables -L -n »òÕß iptablse -t nat -L -n

¶¨Òå²ÎÊý

$DDN_IP="211.101.251.4"

Èç¹ûÄãÒÔÇ°µ÷ÊÔ¹ýiptablesÄÇôÎÒÃÇÏÈÇå³ýÏÈÇ°µÄÉ趨

iptables -F Çå³ýÔ¤Éè±í filter ÖУ¬ËùÓйæÔòÁ´ÖеĹæÔò

iptables -X Çå³ýÔ¤Éè±í filter ÖУ¬Ê¹ÓÃÕß×Ô¶©Á´ÖеĹæÔò

iptables -F -t mangle Çå³ýmangle±íÖУ¬ËùÓйæÔòÁ´ÖеĹæÔò

ÒÔ´ËÀàÍÆ£º

iptables -t mangle -X Çå³ýmangle±íÖУ¬Ê¹ÓÃÕß×Ô¶©Á´ÖеĹæÔò

iptables -F -t nat Çå³ýnat±íÖУ¬ËùÓйæÔòÁ´ÖеĹæÔò

iptables -t nat -X Çå³ýnat±íÖУ¬Ê¹ÓÃÕß×Ô¶©Á´ÖеĹæÔò

Ê×ÏÈÎÒÃÇÀ´ÉèÖà filter table µÄÔ¤Éè²ßÂÔ

ÒýÓÃ:
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT


µ±È»ÎÒÃÇÒ²¿ÉÒÔʹÓÃDROP£¬µ«Ò»°ãÎÒÃDz»»áÕâô×ö

½ÓÏÂÀ´ÅäÖÃnat tables±í

&&Ò»¸öµäÐ͵ÄÀý×ÓIP αװ(SNATÓ¦ÓÃ)£¬¼´¾ÖÓòÍøÍøËùÓеĻúÆ÷¶¼Í¨¹ýeth0×öµÄ͸Ã÷Íø¹Ø³öÈ¥£¬²»×öÆäËûÏÞÖÆ£¬

iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE

¼ÙÈçÄãµÄÉÏÍø·½Ê½ÊÇadsl²¦ºÅÉÏÍø£¬adsl½Ó¿ÚÊÇppp0£¬ÄÇôҲ¿ÉÒÔÕâôÉèÖÃ
iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/24 -j MASQUERADE


ºÃÁË£¬ÏÖÔÚÎÒÃÇÒª°ÑÕâЩÃüÁî±£´æΪ²ßÂÔÎļþ£¬ºÃÈÃiptablesÈϳö

/etc/rc.d/init.d/iptables save ϵͳ»á¸ù¾ÝÄã¸Õ²ÅÊäÈëµÄÃüÁî±£´æΪһ¸ö²ßÂÔÅäÖÃÎļþ/etc/sysconfig/iptables

È»ºóÎÒÃÇÔËÐÐ/etc/rc.d/init.d/iptables start Æô¶¯iptables£¬²¢¼ÓÔØÅäÖÃÎļþ

ºÃÁËÏÖÔÚÄãµÄ¾ÖÓòÍø¿Í»§¶Ë¶¼¿ÉÒÔͨ¹ýÕą̂·þÎñÆ÷ÉÏÍø£¬ftp£¬qq£¬www¶¼Ã»ÓÐÏÞÖÆ£¬ÒòΪÎÒÃÇÏÖÔÚÉèÖõÄÊÇ͸Ã÷µÄ·À»ðǽ¡£ÎÒÃÇ×ܽáһϸղŵÄÃüÁîÊÇ£º


ÒýÓÃ:
Ô´Âë:--------------------------------------------------------------------------------
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT
iptables -t nat -P POSTROUTING ACCEPT
iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE
/etc/rc.d/init.d/iptables save
/etc/rc.d/init.d/iptables start
--------------------------------------------------------------------------------



&&ÁíÍâÒ»¸öµäÐ͵ÄÀý×ÓÊÇDNAT£¬ÀûÓÃתַ¡¢×ª port µÄ·½Ê½£¬Ê¹ÍâÍøµÄ·â°ü£¬¿ÉÒÔµ½´ïÄÚÍøÖеķþÎñÆ÷Ö÷»ú£¬Ë׳ÆÐéÄâÖ÷»ú¡£ÕâÖÖ·½Ê½¿É±£»¤·þÎñÆ÷Ö÷»ú´ó²¿·ÝµÄ port ²»±»Íâ½ç´æÈ¡£¬Ö»¿ª·Å¹«¿ª·þÎñµÄͨµÀ(Èç Web Server port 80)£¬Òò´Ë°²È«ÐԽϸߡ£

±ÈÈ磺 ·²¶Ô 211.101.251.4:80 Á¬ÏßÕß, ÔòתַÖÁ 192.168.0.2:80

iptables -t nat -A PREROUTING -i eth0 -p tcp -d 211.101.251.4 --dprot 80 -j DNAT --to-distination 192.168.0.2:80

ͬÑùDNAT»¹¿ÉÒÔÀûÓÃÔÚDMZÇøÓòµÄmail£¬FTPµÈ·þÎñ£¬´ó¼Ò¾Í°²Ðè×Ô¼ºÐ´°É£¡

ÒÔÉϽ²µÄ²ßÂÔ¶Ô´ó¶àÊýÅóÓÑÀ´ËµÒѾ­´Â´ÂÓÐÓàÁË£¬µ«ÓÐЩ¹«Ë¾µÄÀÏ°å¿É²»ÊÇÕâôÏ룬ÀÏ°åÃÇÍùÍùÏ£ÍûÔ±¹¤ºÃºÃ¹¤×÷£¬³ýÁËÄÜÉÏÍøÊÕÐÅÒÔÍ⣬ÆäËûµÄÖîÈçFTP£¬QQÒ»Âɾ²Ö¹£¬ÕâÑùµÄ»°iptablesµÄÉèÖþͱȽϴó£¬ÎÒÃDz»Äܼòµ¥µÄMASQUERADE¡£±ÈÈçÎÒÃÇÏÖÔÚÖ»¿ª·Å53£¨dns£©80£¬25£¬110Èý¸ö¶Ë¿ÚÓÃÀ´Æ½Ê±µÄwwwºÍmail·þÎñ£¬ÄÇôÎÒÃǾͿÉÒÔÕâÑùÉèÖÃ


Ô´Âë:--------------------------------------------------------------------------------
ptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT
iptables -t nat -P POSTROUTING ACCEPT

iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j SNAT --to-source 211.101.251.4
1192.168.0.0/24 Õâ¸öÍø¶Î£¬Î±×°³É 211.101.251.4 ³öÈ¥¡£

iptables -A OUTPUT -o eth0 -p tcp -s 211.101.251.4 --sport 1024:65535 -d any/0 --dport 80 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp ! --syn -s any/0 --sport 80 -d 211.101.251.4 --dport 1024:65535 -j ACCEPT
¿ª·ÅÄÚÍø¿ÉÒÔ¹Û¿´ÍâÍøµÄÍøÕ¾¡£

iptables -A OUTPUT -o eth0 -p tcp -s 211.101.251.4 --sport 1024:65535 -d any/0 --dport 25 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp ! --syn -s any/0 --sport 25 -d 211.101.251.4 --dport 1024:65525 -j ACCEPT
Äã¿ÉÒÔËÍПø±ðÈË

iptables -A OUTPUT -o eth0 -p tcp -s 211.101.251.4 --sport 1024:65535 -d any/0 --dport 110 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp ! --syn -s any/0 --sport 110 -d 211.101.251.4 --dport 1024:65535 -j ACCEPT
¿ª·ÅÄÚÍø¿ÉÒÔ¶ÔÍâÍøµÄ POP3 server È¡Ðżþ¡£

iptables -A OUTPUT -o eth0 -p udp -s 211.101.251.4 --sport 1024:65535 -d any/0 --dport 53 -j ACCEPT
iptables -A INPUT -i eth0 -p udp -s any/0 --sport 53 -d 211.101.251.4 --dport 1024:65535 -j ACCEPT
¿ª·Å²éѯÍâÍøµÄ DNS Ö÷»ú

iptables -A OUTPUT -o eth0 -p icmp -s 211.101.251.4 --icmp-type 8 -d any/0 -j ACCEPT
iptables -A INPUT -i eth0 -p icm -s any/0 --icmp-type 0 -d 211.101.251.4 -j ACCEPT
¿ª·Å ping¹¦ÄÜ



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ÕâÀﻹҪ½²µÄÊÇÎҵķþÎñÆ÷ÊÇÔËÐÐ×Åsquid·þÎñ£¬ÓÉÓÚ´ø¿íÓÐÏÞ£¬ËùÒÔËäÈ»¿ªÁË͸Ã÷SNAT¹¦ÄÜ£¬µ«»¹ÊÇÏ£Íû¿Í»§¶ËÌرðÊÇwwwµÄ·ÃÎÊ»¹ÊÇʹÓÃsquid·þÎñ£¬ÕâÑù¿ÉÒÔ½ÚÊ¡²»ÉÙ´ø¿í×ÊÔ´£¬ÕâÀïÎÒÃǾͿÉÒÔÓõ½iptablesµÄTransparent¹¦ÄÜ£¬ÈÃiptablesµÄ¿Í»§¶Ë80¶Ë¿ÚµÄ·ÃÎÊÇ¿ÐÐתÒƵ½squidµÄ3128¶Ë¿Ú£¬

Ê×ÏÈ£¬ÐÞ¸Ä /etc/squid/squid.conf£¬ÕÒµ½ÏÂÃ漸ÐУ¬²¢ÐÞ¸ÄΪÈçÏÂÑù×Ó£º

httpd_accel_host redhat.frankhome.com # ÇëÐÞ¸ÄΪÄúµÄ squid Ö÷»úÃû³Æ
httpd_accel_port 80
httpd_accel_with_proxy on
httpd_accel_uses_host_header on
È»ºó/etc/rc.d/init.d/squid restart

½Ó×ÅÌí¼ÓÒÔϲßÂÔ£º
iptables -t nat -A PREROUTING -i eth1 -p tcp -s 192.168.0.0/24 --dport 80 -j REDIRECT --to-ports 3128

Õâʱºò£¬ÄúµÄ Transparent Proxy ¾ÍÆðÀ´ÁË£¡Èç¹ûÄúÒª²âÊÔËü£¬¿ÉÒÔÈ¡Ïû client ¶ËµÄ proxy É趨£¬²¢½« squid¹Ø±Õ£¬È»áá²âÊÔÊÇ·ñ²»ÄÜÁ¬Ïß(½¨ÒéÓÃÒ»¸öδÔøä¯ÀÀ¹ýµÄÍøÖ·À´²âÊÔ)£¿È»Ôò£¬ÔÙ½« squid´ò¿ª£¬Èç¹ûÄÜÕâÑùÓÖÄָܻ´Á¬ÏߵĻ°£¬ÄǾÍÒѾ­³É¹¦ÁË£¡ÕâÑùÓÐÒ»¸öºÃ´¦ÊÇ£ºÒÔááÄúÔÙÒ²²»±ØÅܵ½ client ÄDZßÉ趨 proxy£»¶øÇÒ£¬¸üºÃµÄµØ·½ÔÚ춣ºÖظ´ÐÔµÄÁ¬ÏßÔÙÒ²ÎÞÐèÕ¼Óñ¦¹óµÄ¶ÔÍâƵ¿í£¬Ëٵݵ±È»Ò²ÄÜ'¼ÙÐÔ'µÄ»ñµÃÌá¸ß

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