{"id":356,"date":"2013-07-02T06:20:11","date_gmt":"2013-07-02T06:20:11","guid":{"rendered":"http:\/\/www.selinuxplus.com\/?p=356"},"modified":"2013-07-02T06:22:51","modified_gmt":"2013-07-02T06:22:51","slug":"linux%e7%b3%bb%e7%bb%9f%e7%ae%a1%e7%90%86_iptables","status":"publish","type":"post","link":"http:\/\/www.selinuxplus.com\/?p=356","title":{"rendered":"Linux\u7cfb\u7edf\u7ba1\u7406_iptables"},"content":{"rendered":"

1 \u6982\u8ff0<\/h2>\n

\u00a0\u9632\u706b\u5899\u7684\u5e94\u7528\u5728linux\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u53ca\u5176\u5e38\u89c1\uff0c\u672c\u6587\u7701\u53bb\u4e00\u4e9b\u7b80\u5355\u7684\u6280\u672f\u4ecb\u7ecd\uff0c\u76f4\u63a5\u8fdb\u5165\u4e3b\u9898\u4ecb\u7ecd\u9632\u706b\u5899\u7684\u4e00\u4e9b\u6df1\u5ea6\u77e5\u8bc6\u3002<\/p>\n

2 \u9632\u706b\u5899\u7684\u57fa\u672c\u6982\u5ff5<\/strong><\/h2>\n

\u00a0\u9632\u706b\u5899\u7684\u4efb\u52a1\u7b80\u5355\u7684\u63cf\u8ff0\u5c31\u662f\u653e\u884c\u5408\u6cd5\uff0c\u6216\u5c01\u9501\u4e0d\u5408\u6cd5\u7684\u5c01\u5305\uff0c\u5173\u4e8e\u4ec0\u4e48\u662f\u9632\u706b\u5899\u8fd9\u91cc\u5c31\u4e0d\u505a\u4ecb\u7ecd\u4e86\u3002<\/p>\n

2.1 \u9632\u706b\u5899\u7684\u5224\u522b\u4f9d\u636e<\/h3>\n

\u5404\u5c42\u5c01\u88c5\u5305\u5305\u5934\u4fe1\u606f\uff1a<\/p>\n

1 \u94fe\u63a5\u5c42\u4fe1\u606f\uff1a<\/p>\n

\u83b7\u53d6\u8fde\u63a5\u5c42\u4fe1\u606f\u4e0d\u662f\u5f88\u96be\uff1a\u5982\uff1a<\/p>\n

[root@fc16 \/]# ssh 112.64.161.xx\r\nroot@112.64.161.xx's password:<\/pre>\n
\u6211\u4eec\u4f7f\u7528tcpdump\u6251\u6349\u4fe1\u606f\uff1a<\/p>\n
[root@fc16 \/]# tcpdump -A host 192.168.0.196 -e \r\ntcpdump: verbose output suppressed, use -v or -vv for full protocol decode\r\nlistening on wlan0, link-type EN10MB (Ethernet), capture size 65535 bytes\r\n12:50:04.267060 8c:a9:82:3a:88:f8 (oui Unknown) > 00:21:91:6f:dd:be (oui Unknown), ethertype IPv4 (0x0800), length 74: 192.168.0.196.43519 > 112.64.161.xx.ssh: Flags [S], seq 1615294735, win 14600, options [mss 1460,sackOK,TS val 2067145 ecr 0,nop,wscale 7], length 0\r\nE..<..@.@.l.....p@......`Gq.......9..\t.........<\/pre>\n
\u4ece\u6240\u663e\u793a\u7684\u5185\u5bb9\uff0c\u6700\u4e3a\u91cd\u8981\u7684\u83ab\u8fc7\u4e8eMAC address\uff0c\u6211\u4eec\u53ef\u4ee5\u5728\u9632\u706b\u5899\u7684\u8fc7\u6ee4\u89c4\u5219\u4e2d\u501f\u52a9Destination MAC\u6765\u5224\u522b\u5c01\u5305\u662f\u6709\u90a3\u4e2a\u4e3b\u673a\u53d1\u8fc7\u6765\u7684\u3002
\n2 \u7f51\u7edc\u5c42
\n\u83b7\u53d6\u7f51\u7edc\u5c42\u7684\u4e3b\u8981\u4e3aIP\u5305\u5934\uff0c\u5176\u5305\u5934\u6709\u5f88\u591a\u53ef\u7528\u4fe1\u606f\u662f\u53ef\u4ee5\u4f5c\u4e3a\u8fc7\u6ee4\u6761\u4ef6\u7684\u3002<\/p>\n
[root@fc16 \/]# tcpdump -A host 192.168.0.196  -X\r\n13:02:10.150183 IP 192.168.0.196.36576 > 192.168.1.1.domain: 62380+ PTR? 46.161.64.112.in-addr.arpa. (44)\r\n\t0x0000:  4500 0048 9e44 4000 4011 194b c0a8 00c4  E..H.D@.@..K....\r\n\t0x0010:  c0a8 0101 8ee0 0035 0034 e059 f3ac 0100  .......5.4.Y....\r\n\t0x0020:  0001 0000 0000 0000 0234 3603 3136 3102  .........46.161.\r\n\t0x0030:  3634 0331 3132 0769 6e2d 6164 6472 0461  64.112.in-addr.a\r\n\t0x0040:  7270 6100 000c 0001                      rpa.....\r\n13:02:10.157083 IP 192.168.1.1.domain > 192.168.0.196.36576: 62380 NXDomain 0\/1\/0 (106)\r\n\t0x0000:  4500 0086 0000 4000 4011 b751 c0a8 0101  E.....@.@..Q....\r\n\t0x0010:  c0a8 00c4 0035 8ee0 0072 050a f3ac 8183  .....5...r......\r\n\t0x0020:  0001 0000 0001 0000 0234 3603 3136 3102  .........x6.161.\r\n\t0x0030:  3634 0331 3132 0769 6e2d 6164 6472 0461  64.112.in-addr.a\r\n\t0x0040:  7270 6100 000c 0001 c00f 0006 0001 0000  rpa.............\r\n\t0x0050:  0e10 0032 0764 6e73 2d63 686a 0273 6806  ...2.dns-chj.sh.\r\n\t0x0060:  636e 636e 6574 036e 6574 0004 726f 6f74  cncnet.net..root\r\n\t0x0070:  c038 0132 68a8 0000 0e10 0000 0708 0001  .8.2h...........\r\n\t0x0080:  5180 0000 0e10<\/pre>\n
\u4ece\u4e0a\u56fe\u53ef\u4ee5\u5f97\u5230\u4e00\u4e9b\u6211\u4eec\u60f3\u8981\u7684\u4fe1\u606f\uff1a
\n0x0000 \u4ee3\u8868IP\u5305\u5934
\n4500 0048 9e44 4000 4011 194b c0a8 00c4
\n\u8fd9\u6bb5\u4fe1\u606f\u5206\u522b\u8868\u793a\uff1a
\n4500\uff1b4\u4ee3\u8868ipv4\uff0c5\u4ee3\u8868IP\u5305\u5934\u957f\u5ea6\u4e3a5\u4e2a32bit\uff0832bit\u4e5f\u5c31\u662f4\u4e2a\u5b57\u8282\uff0900\u4ee3\u8868TOS\uff08000 0000 0\uff09\u524d3\u4e2abit\u7684\u4f18\u5148\u6743\uff0c\u73b0\u5df2\u5ffd\u7565\uff0c4bit\u7684TOS\u5206\u522b\u4e3a\u6700\u5c0f\u5ef6\u65f6\uff0c\u6700\u5927\u541e\u5410\u91cf\uff0c\u6700\u9ad8\u53ef\u9760\u6027\uff0c\u548c\u6700\u5c0f\u8d39\u7528
\n0048-\u603b\u957f\u5ea6\uff08\u6570\u636e\u5305\u603b\u957f\u5ea6\uff1a\u5934\u90e8 + \u6570\u636e\u957f\u5ea6\uff09
\n9e44\uff1b\u4ee3\u8868\u552f\u4e00\u6807\u793a\u7b26
\n4000\uff1b\u4ee3\u8868\u4e0d\u5206\u7247\uff0c\u5176\u662f\u6807\u8bc6\u5b57\u6bb5\uff0c\u548c\u7247\u504f\u79fb
\n4011\uff1b40\u4ee3\u8868\u751f\u5b58\u65f6\u95f4TTL\uff0c11\uff08\u4e0a\u5c42\u534f\u8bae\u53f7\uff0c11upd\uff0c6tcp 255 RAW\uff09
\n194b\uff1b\u4ee3\u8868\u6821\u9a8c\u503c\u3002
\nCoa8 00c4 \u4ee3\u8868 SRC IP\uff0c\u6e90IP\uff0c\u53ef\u4ee5inet_ntoa\u8f6c\u6362\u6210\u70b9\u53f7\u5206\u9694\u7684IP\u3002
\n0x0010: c0a8 0101
\ncoa8 \u4ee3\u8868\u76ee\u6807IP\u3002
\n3 \u4f20\u8f93\u5c42<\/p>\n
    192.168.0.196.44452 > 112.64.161.xx.ssh: Flags [.], cksum 0xd301 (incorrect -> 0x1c1f), ack 877, win 136, options [nop,nop,TS val 4406110 ecr 446676163], length 0\r\n\t0x0000:  4500 0034 b095 4000 4006 b753 c0a8 00c4  E..4..@.@..S....\r\n\t0x0010:  7040 a12e ada4 0016 041b 8e8b d1fb 61da  p@............a.\r\n\t0x0020:  8010 0088 d301 0000 0101 080a 0043 3b5e  .............C;^\r\n\t0x0030:  1a9f bcc3<\/pre>\n
\u4f20\u8f93\u5c42\u53ef\u4ee5\u83b7\u53d6\u7684\u4fe1\u606f\u6709\u5f88\u591a\uff0c\u5982\u7aef\u53e3\u53f7\uff0ctcp\u957f\u5ea6\uff0cflags\u6807\u51c6\u4e3a\u7b49\u3002
\n\u9632\u706b\u5899\u7684\u5206\u7c7b\uff1a
\n\u5305\u8fc7\u6ee4\u9632\u706b\u5899\uff0c\u5e94\u7528\u5c42\u9632\u706b\u5899\uff0c
\n\u5e38\u89c1\u7684\u9632\u706b\u5899\u7ed3\u6784\uff1a
\n\u5355\u673a\u9632\u706b\u5899\uff0c\u7f51\u5173\u5f0f\u9632\u706b\u5899\uff0c\u901a\u900f\u5f0f\u9632\u706b\u5899
\n\u8fd9\u91cc\u7b80\u5355\u7684\u4ecb\u7ecd\u4e00\u4e0b\u901a\u900f\u5f0f\u9632\u706b\u5899\uff0c\u901a\u900f\u5f0f\u9632\u706b\u5899\u5c31\u662f\u4e00\u4e2abridge\u8bbe\u5907\uff0c\u5e76\u4e14\u5728bridge\u8bbe\u5907\u4e0a\u8d4b\u4e88filter\u7684\u80fd\u529b\uff0c\u56e0\u4e3abridge\u662f\u5de5\u4f5c\u4e8eOSI\u7b2c\u4e8c\u5c42\u7684\u7f51\u7edc\u8bbe\u5907\uff0c\u56e0\u6b64\u4e0d\u4f1a\u6709\u4efb\u4f55Routing\u7684\u95ee\u9898\uff0c\u5e76\u4e14Bridge\u4e0a\u4e0d\u9700\u8981\u6307\u5b9a\u4efb\u4f55IP\uff0c\u8fd9\u6837\u6ca1\u6709\u201cRouting\u201d\u7684\u95ee\u9898\uff0c\u9632\u706b\u5899\u4e3b\u673a\u672c\u8eab\u65e0\u987b\u6307\u5b9aIP\u3002\u56e0\u6b64\uff0c\u901a\u900f\u5f0f\u9632\u706b\u5899\u7684\u90e8\u7f72\u80fd\u529b\u4e5f\u662f\u76f8\u5f53\u5f3a\u3002<\/p>\n
3 \u9632\u706b\u5899\u547d\u4ee4\u7ed3\u6784<\/h2>\n
Netfilter\u5206\u4e3a4\u4e2aTable\uff0c\u5206\u522b\u4e3aFilter,NAT,Mangle,\u4ee5\u53caRAW\u3002
\nTable Chain
\nFilter \u00a0 \u00a0 \u00a0 \u00a0 \u00a0INPUT,FORWARD,OUTPUT
\nNat \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0PREROUTING,POSTROUTING,OUTPUT
\nMangle \u00a0 \u00a0 \u00a0PROROUTING,INPUT,FORWARD,OUTPUT,POSTROUTING
\nRAW \u00a0 \u00a0 \u00a0 \u00a0 \u00a0PREROUTING,OUTPUT
\nFilter:Filter\u662fnetfilter\u5185\u6700\u4e3a\u91cd\u8981\u7684\u673a\u5236\uff0c\u5176\u4efb\u52a1\u4e3a\u6267\u884c\u5c01\u5305\u7684\u8fc7\u6ee4\u52a8\u4f5c\uff0c\u4e5f\u5c31\u662f\u9632\u706b\u5899\u7684\u529f\u80fd\uff1b
\nNAT\uff08Network address Translation\uff09\u4e5f\u662f\u9632\u706b\u5899\u4e0d\u53ef\u6216\u7f3a\u7684\u91cd\u8981\u673a\u5236\uff0c\u5176\u4e3b\u8981\u529f\u80fd\u901a\u4fd7\u7684\u8bf4\u5c31\u662fIP\u5206\u4eab\u5668\u3002
\nMangle\uff1bMangle\u662f\u4e00\u4e2a\u7279\u6b8a\u7684\u673a\u5236\uff0c\u53ef\u4ee5\u501f\u52a9Mangle\u4fee\u6539\u884c\u5f84\u9632\u706b\u5899\u5185\u7684\u5c01\u5305\uff0c
\nRAW \uff1a\u8d1f\u8d23\u52a0\u5feb\u5c01\u5305\u7a7f\u8d8a\u9632\u706b\u5899\u673a\u5236\u7684\u901f\u5ea6\uff0c\u501f\u6b64\u63d0\u9ad8\u9632\u706b\u5899\u7684\u529f\u80fd\u3002<\/p>\n
\u5728\u505a\u9632\u706b\u5899\u7b56\u7565\u7684\u65f6\u5019\uff0c\u8981\u4e3a\u6bcf\u4e2aChain\u51c6\u5907\u4e00\u4e2aDefault Policy\uff0c\u4e0d\u7ba1Chain\u6709\u591a\u5c11\u89c4\u5219\uff0cDefault Policy\u6c38\u8fdc\u5728\u6bcf\u4e2aChain\u7684\u4f4e\u7aef\u3002
\n\u5f53\u4e00\u4e2a\u5c01\u5305\u8fdb\u5165INPUT china\u4e4b\u540e\uff0cFilter\u673a\u5236\u5373\u4f1a\u4ee5\u8fd9\u4e2a\u5c01\u5305\u7684\u7279\u5f81\u4eceINPUT china\u4e4b\u5185\u7684\u7b2c\u4e00\u6761\u89c4\u5219\u9010\u4e00\u7684\u5411\u4e0b\u5339\u914d\uff0c\u5339\u914d\u7684\u89c4\u5219\u65b9\u5f0f\u4e3a\u201cirst match\u201d \u5373\u6240\u8c13\u7684\u201c\u4f18\u5148\u6267\u884c\u201d\u3002
\n\u6211\u4eec\u5e38\u542c\u8bf4Linux\u9632\u706b\u5899\u53eb\u505aIptables\uff0c\u5176\u5b9e\u8fd9\u6837\u7684\u79f0\u6cd5\u662f\u4e0d\u6b63\u786e\u7684\uff0c\u90a3\u4e48Iptables\u662f\u4ec0\u4e48\u5462\uff0cNetfilter\u6240\u9700\u8981\u7684\u89c4\u5219\u662f\u586b\u5199\u5728\u5185\u5b58\u91cc\uff0c\u4f46\u95ee\u9898\u662f\u9632\u706b\u5899\u7ba1\u7406\u4eba\u5458\u5982\u4f55\u5c06\u89c4\u5219\u586b\u5199\u5230\u5185\u5b58\u5462\uff0c\u56e0\u6b64\u7ba1\u7406\u4eba\u6e90\u9700\u8981\u4e00\u4e2a\u89c4\u5219\u7f16\u8f91\u5de5\u5177\uff0c\u901a\u8fc7\u8fd9\u4e2a\u5de5\u5177\u6765\u5bf9\u5185\u5b58\u7684\u89c4\u5219\u8fdb\u884c\u65b0\u589e\uff0c\u4fee\u6539\u548c\u5220\u9664\uff0c\u8fd9\u4e2a\u7f16\u8f91\u5de5\u5177\u5c31\u662fiptables\u4ee5\u53caip6tables\u3002
\nNetfilter\u7684\u652f\u6301\u7684\u6a21\u5757\u8d8a\u591a\uff0c\u9632\u706b\u5899\u7684\u529f\u80fd\u4e5f\u5c31\u4f1a\u8d8a\u591a\uff0c\u800c\u4e14\u6211\u4eec\u53ef\u4ee5\u501f\u52a9\u5347\u7ea7Kernel\u7684\u65b9\u6cd5\u8fbe\u5230\u987a\u4fbf\u5347\u7ea7Netfilter\u7684\u76ee\u7684\uff0c\u4e0d\u8fc7\u9632\u706b\u5899\u5347\u7ea7\u4e0d\u5355\u5355\u662f\u5347\u7ea7kernel\u5c31\u53ef\u4ee5\u89e3\u51b3\u7684\uff0c\u4e5f\u5e76\u975e\u4e00\u5473\u589e\u52a0netfilter\u6a21\u5757\u5c31\u53ef\u4ee5\u65e0\u9650\u6269\u5145Netfilter\u7684\u529f\u80fd\uff0c\u6211\u4eec\u77e5\u9053\u7ba1\u7406\u4eba\u5458\u501f\u52a9iptables\u5de5\u5177\uff0c\u628a\u89c4\u5219\u586b\u5199\u5230netfilter\u7684\u89c4\u5219\u6570\u636e\u5e93\u4e2d\uff0c\u800c\u8fd9\u91cc\u5c31\u9700\u8981\u7279\u5b9a\u7684\u8bed\u6cd5\uff0c\u6211\u4eec\u5c06\u89c4\u5219\u7ed9iptables\u4ea4\u7ed9iptables\u5de5\u5177\u65f6\uff0ciptables\u5de5\u5177\u4f1a\u9996\u5148\u68c0\u67e5\u8bed\u6cd5\u662f\u5426\u6b63\u786e\u3002\u4f46iptables\u662f\u600e\u4e48\u83b7\u5f97\u65b0\u6a21\u5757\u7684\u8bed\u6cd5\u7ed3\u6784\u5462\u3002
\n\u5b9e\u65f6\u4e0aiptables \u4e5f\u6709\u6a21\u5757\uff0c\u8fd9\u4e9b\u6a21\u5757\u653e\u5728\/lib\/iptables\u76ee\u5f55\u4e0b\u3002fc16\u7684\u7ed3\u6784\u6709\u70b9\u53d8\u5316\uff0c\u4e3a\uff1a<\/p>\n
[root@fc16 ~]# ls \/lib64\/xtables\/\r\nlibip6t_ah.so          libipt_unclean.so     libxt_NFQUEUE.so\r\nlibip6t_dst.so         libxt_AUDIT.so        libxt_NOTRACK.so\r\nlibip6t_eui64.so       libxt_CHECKSUM.so     libxt_osf.so\r\nlibip6t_frag.so        libxt_CLASSIFY.so     libxt_owner.so\r\nlibip6t_hbh.so         libxt_cluster.so      libxt_physdev.so\r\nlibip6t_hl.so          libxt_comment.so      libxt_pkttype.so\r\nlibip6t_HL.so          libxt_connbytes.so    libxt_policy.so\r\nlibip6t_icmp6.so       libxt_connlimit.so    libxt_quota.so\r\nlibip6t_ipv6header.so  libxt_connmark.so     libxt_rateest.so<\/pre>\n
\u4e0b\u56fe\u4e3aiptables\u8bbf\u95ee\u7684\u6d41\u7a0b\u56fe
\n\"\"<\/a>
\n\u9632\u706b\u5899\u7684\u89c4\u5219\u4e0d\u5728\u8fd9\u91cc\u7ec6\u8bf4\u4e86\uff0c\u672c\u6587\u4e3b\u8981\u6d89\u53ca\u7684\u662f\u7406\u8bba\u4e0a\u7684\u57fa\u7840\u77e5\u8bc6\u3002\u8fd9\u91cc\u4ecb\u7ecd\u4ee5\u4e0b\u5bf9\u5916\u5efa\u7acb\u94fe\u63a5\u65f6\u7684\u95ee\u9898<\/p>\n
4 \u89e3\u51b3\u65e0\u6cd5\u5728\u9632\u706b\u5899\u4e3b\u673a\u4e0a\u5bf9\u5916\u5efa\u7acb\u94fe\u63a5\u7684\u95ee\u9898<\/h2>\n
\u5728\u5e38\u89c4\u6a21\u5f0f\u4e0b\uff0c\u5ba2\u6237\u7aef\u5fc5\u987b\u4f7f\u7528\u5927\u4e8e1024\u7684\u7aef\u53e3\uff0c\u5982\u679c\u5c06\u5927\u4e8e1024\u7684\u7aef\u53e3\u90fd\u6253\u5f00\uff0c\u5bf9\u4e8e\u9632\u706b\u5899\u7684\u9650\u5236\u539f\u5219\u662f\u65e0\u6cd5\u63a5\u53d7\u7684\uff0c\u5728netfilter\/iptables\u91cc\u4f7f\u7528\u4e86\u201c\u94fe\u63a5\u8ffd\u8e2a\u201d\u7684\u529f\u80fd\uff0c\u8fd9\u4e2a\u529f\u80fd\u6709x_state.ko\u6a21\u5757\u6240\u63d0\u4f9b\u3002
\nX_state.ko\u5728iptables\u53eb\u505astate\uff0c\u6211\u4eec \u77e5\u9053\u5728TCP\/TP \u89c4\u8303\u4e2d\uff0c\u94fe\u63a5\u72b6\u6001\u4e3a12\u4e2d\uff0c\u8fd912\u79cd\u5206\u522b\u4e3a\uff1aESTABLISHED\u3001SYS_SENT\u3001SYN_RECV\u3001 FIN_WAIT1\u3001 FIN_WAIT2\u3001 TIME_WAIT\u3001 CLOSED\u3001 CLOSE_WAIT\u3001 LAST_ACK\u3001 LISTEN\u3001 CLOSEING\u3001 UNKNOWN\u3002 \u8fd912\u79cd\u72b6\u6001\u5728TCP\u7684\u4e09\u6b21\u63e1\u624b\u548c\u56db\u6b21\u65ad\u5f00\u4e2d\u7ecf\u5e38\u4f7f\u7528\uff0c\u800cstate\u6a21\u5757\u53ea\u67094\u4e2d\u72b6\u6001\uff0c\u5206\u522b\u4e3aESTABLISHED\uff0cNEW\uff0cRELATE\uff0cINVALID\u3002\u8fd94\u4e2a\u72b6\u6001\u548cTCP\/IP\u768412\u4e2d\u72b6\u6001\u4e0d\u80fd\u6df7\u4e3a\u4e00\u8c08\uff0c\u56e0\u4e3a\u4e24\u8005\u662f\u5b8c\u5168\u4e0d\u76f8\u5173\u7684\u5b9a\u4e49\uff0c\u4f8b\u5982\u5728TCP\/IP\u6807\u51c6\u72b6\u6001\u63cf\u8ff0\u4e0b\uff0cUDP\u548cICMP\u5c01\u5305\u662f\u6ca1\u6709\u94fe\u63a5\u72b6\u6001\u7684\uff0c\u800c\u5728state\u6a21\u5757\u4e0b\u662f\u6709\u94fe\u63a5\u72b6\u6001\u7684\u3002<\/p>\n
4.1 ESTABLISHED<\/h3>\n
\"\"<\/a>
\n\u6211\u4eec\u770b\u5230\u4e0a\u56fe\u6709\u4e00\u4e2a\u8fd9\u6837\u7684\u4f8b\u5b50\uff0c\u7b2c\u4e00\u4e2a\u94fe\u63a5\u4e3aTCP\u5c01\u5305\u7684\u5173\u7cfb\uff0c\u7b2c\u4e8c\u4e2a\u4e3aUDP\u5c01\u5305\u7684\u5173\u7cfb\uff0c\u7b2c\u4e09\u4e2a\u5219\u662fICMP\u5c01\u5305\u7684\u5173\u7cfb\uff0c\u8fd9\u91cc\u7b80\u8981\u4ecb\u7ecd\u8fd9\u4e09\u79cd\u5173\u7cfb\u3002
\nTCP\u5c01\u5305\u5173\u7cfb\uff1a\u5ba2\u6237\u7aef\u6267\u884cssh client\uff0c\u5bf9\u7f51\u7edc\u4e0a\u7684ssh server\u53d1\u8d77\u8bbf\u95ee\u8bf7\u6c42\uff0c\u8fd9\u662f\u9001\u51fa\u7684\u7b2c\u4e00\u4e2a\u5c01\u5305\u5c31\u662f\u670d\u52a1\u5668\u8bf7\u6c42\u7684\u5c01\u5305\uff0c\u5982\u679c\u8fd9\u4e2a\u5c01\u5305\u80fd\u591f\u6210\u529f\u7a7f\u8d8a\u9632\u706b\u5899\uff0c\u90a3\u4e48\u63a5\u4e0b\u6765\u76841\uff0c2\u7684\u65b9\u5411\u6240\u6709\u5c01\u5305\u7684\u72b6\u6001\u90fd\u662fESTABLISHED\u3002
\nUDP\u5c01\u5305\u5173\u7cfb\uff0cfirefox\u8bf7\u6c42\u8bbf\u95ee\u670d\u52a1\uff0cfirefox\u9996\u5148\u8bf7\u6c42DNS\u89e3\u6790\u670d\u52a1\uff0cfirefox\u4f1a\u60f3DNS\u53d1\u9001\u4e00\u4e2a\u5c01\u5305\uff0c\u4ee5\u8bf7\u6c42\u540d\u79f0\u89e3\u6790\uff0c\u5982\u679c\u80fd\u591f\u901a\u8fc7\u9632\u706b\u5899\uff0c\u5219\u57283\uff0c4\u65b9\u5411\u7684\u6240\u6709\u5c01\u5305\u7684\u72b6\u6001\u90fd\u662fESTABLISHED\u3002
\nICMP\u5c01\u5305\u5173\u7cfb\u3002\u5ba2\u6237\u7aef\u63d0\u51faping\u8bf7\u6c42\uff0cping\u53d1\u9001\u4e00\u4e2aICMP\u5c01\u5305\u7ed9\u670d\u52a1\u5668\uff0c\u5982\u679c\u8fd9\u4e2a\u5c01\u5305\u80fd\u591f\u901a\u8fc7\u9632\u706b\u5899\uff0c\u5219\u57285\uff0c6\u65b9\u5411\u7684\u6240\u6709\u5c01\u5305\u72b6\u6001\u90fd\u662fESTABLISHED\u3002
\n\u7efc\u4e0a\u6240\u8ff0\uff0c\u53ea\u8981\u5c01\u5305\u80fd\u591f\u6210\u529f\u7a7f\u8d8a\u9632\u706b\u5899\uff0c\u90a3\u4e48\u4e4b\u540e\u6240\u6709\u5c01\u5305\u7684\u72b6\u6001\uff0c\u5305\u62ec\u53cd\u5411\u6240\u6709\u7684\u5c01\u5305\u72b6\u6001\u90fd\u662fESTABLISHED\u3002
\n\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u7684\u65b9\u6cd5\uff0c\u5219\u662f\u6709state\u6a21\u5757\u7684ESTABLISHED\u72b6\u6001\u3002
\n\u5982\uff1a<\/p>\n
itables -A _INPUT -m state \u2013state ESTABLISHED -j ACCEPT.<\/pre>\n
4.2 NEW<\/h3>\n
NEW\u4e0e\u534f\u8bae\u5b8c\u5168\u65e0\u5173\uff0c\u5176\u6240\u6307\u7684\u662f\u6bcf\u4e00\u6761\u94fe\u63a5\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5c01\u5305\uff0c\u4ed6\u662f\u6307\u4e00\u6761\u8fde\u63a5\u4e2dSYN=1\u7684\u90a3\u4e2a\u5c01\u5305\uff0c\u5728\u94fe\u63a5\u4e2d\uff0c\u7b2c\u4e00\u4e2a\u5c01\u5305\u4e3b\u8981\u7528\u6765\u505a\u5b89\u5168\u5904\u7406\u3002<\/p>\n
\n4.3 RELATED<\/h3>\n
\nRELATED\u662f\u6307\u88ab\u52a8\u4ea7\u751f\u7684\u54cd\u5e94\u5c01\u5305\uff0c\u800c\u4e14\u8fd9\u4e2a\u5c01\u5305\u4e0d\u5c5e\u4e8e\u73b0\u6709\u7684\u4efb\u4f55\u94fe\u63a5\u7684\u5c01\u5305\u3002
\n\u5982<\/p>\n
traceroute to 112.64.161.xx (112.64.161.xx), 30 hops max, 60 byte packets\r\n 1  192.168.0.1 (192.168.0.1)  1.600 ms  4.060 ms  4.674 ms\r\n 2  192.168.1.1 (192.168.1.1)  9.353 ms  10.142 ms  11.623 ms\r\n 3  1.60.79.218.broad.xw.sh.dynamic.163data.com.cn (218.79.60.1)  12.200 ms  12.968 ms  14.723 ms\r\n 4  124.74.59.149 (124.74.59.149)  14.886 ms  15.028 ms  15.129 ms\r\n 5  124.74.210.153 (124.74.210.153)  98.695 ms  99.076 ms  99.503 ms\r\n 6  61.152.86.46 (61.152.86.46)  15.050 ms  7.124 ms  7.280 ms\r\n 7  202.97.50.138 (202.97.50.138)  8.162 ms  8.551 ms  20.744 ms\r\n 8  * * *\r\n 9  219.158.21.229 (219.158.21.229)  19.742 ms  19.930 ms  20.256 ms\r\n10  219.158.98.158 (219.158.98.158)  123.986 ms  124.367 ms *\r\n11  112.64.243.74 (112.64.243.74)  30.387 ms  31.709 ms  32.250 ms\r\n12  112.64.250.154 (112.64.250.154)  23.874 ms  20.964 ms  21.737 ms\r\n13  112.64.161.xx (112.64.161.xx)  20.692 ms  19.687 ms  19.178 ms<\/pre>\n
\u4e0a\u56fe\u4e3atraceroute\u7684\u4e00\u4e2a\u5b9e\u9a8c\uff0c\u5f53 192.168.0.1\u6536\u5230\u5c01\u5305\u540e\uff0c\u5c06\u5c01\u5305\u7684TTL\u503c\u51cf1\uff0c\u5e76\u53d1\u9001\u7ed9\u4e3b\u673a\u4e00\u4e2aICMP\u534f\u8bae\u7684\u6570\u636e\u5305\uff0c\u5c06\u6570\u636e\u5305\u4f20\u7ed9\u4e0b\u4e00\u4e2a\u4e3b\u673a192.168.1.1,\u5982\u6b64\u7c7b\u540c\uff0c\u800c\u4f20\u7ed9\u670d\u52a1\u5668\u7684\u90a3\u4e2aICMP\u5c01\u5305\u7684\u72b6\u6001\u662fRELATED\u3002
\n\u8fd9\u91cc\u9700\u8981\u8bf4\u660e\u7684\u662f\uff0cRELATE\u4e0e\u534f\u8bae\u65e0\u5173\uff0c\u53ea\u8981\u56de\u5e94\u6765\u7684\u5c01\u5305\u662f\u56e0\u4e3a\u672c\u673a\u5148\u9001\u51fa\u53bb\u7684\u4e00\u4e2a\u5c01\u5305\u5bfc\u81f4\u53e6\u4e00\u4e2a\u8fde\u63a5\u4ea7\u751f\uff0c\u800c\u8fd9\u4e00\u6761\u65b0\u94fe\u63a5\u4e0a\u7684\u6240\u6709\u5c01\u5305\u90fd\u5c5e\u4e8eRELATED\u72b6\u6001\u7684\u5c01\u5305\u3002<\/p>\n
4.4 INVALID<\/h3>\n
INVALID\u72b6\u6001\u662f\u6307\u72b6\u6001\u4e0d\u660e\u7684\u5305\uff0c\u4e0d\u5c5e\u4e8e\u4e0a\u9762\u4e09\u79cd\u72b6\u6001\uff0c\u56e0\u6b64\u4e00\u822c\u89c6\u8fd9\u79cd\u72b6\u6001\u4e3a\u6076\u610f\u8f6f\u4ef6\u5305\uff0cDROP\u6389\u3002<\/p>\n
Iptables -A INPUT -p all -m  state \u2013state INVALID -j DROP<\/pre>\n
5 Netfilter\/iptables \u9ad8\u7ea7\u6280\u5de7<\/h2>\n
iptables\u7684\u57fa\u672c\u89c4\u5219\u8fd9\u91cc\u5c31\u4e0d\u591a\u8bb2\u4e86\uff0c\u4e92\u8054\u7f51\u4e0a\u8fd9\u65b9\u9762\u8d44\u6599\u662f\u5f88\u5168\u9762\u7684\uff0c\u5728\u5199\u5b8c\u7b56\u7565\u7684\u65f6\u5019\uff0c\u6ce8\u610f\u5bf9\u7b56\u7565\u7684\u4f18\u5316\uff0c\u9632\u706b\u5899\u7684\u5339\u914d\u89c4\u5219\u4ece\u4e0a\u81f3\u4e0b\uff0c\u5199\u7b56\u7565\u8981\u628a\u63e1\u597d\u4e00\u4e2a\u539f\u5219\u5c31\u662f\uff1a
\n\u8d8a\u70ed\u95e8\uff08\u5339\u914d\u547d\u4e2d\u6b21\u6570\u8d8a\u9ad8\u8005\uff09\u89c4\u5219\u8d8a\u5199\u5728\u524d\u9762\uff0c\u4e0d\u8fc7\u6709\u65f6\u5019\u6211\u4eec\u96be\u8861\u91cf\u90a3\u4e2a\u670d\u52a1\u4e5f\u6bd4\u8f83\u70ed\u95e8\uff0cnetfilter\u8bbe\u8ba1\u4e86\u4e00\u4e2a\u7edf\u8ba1\u529f\u80fd<\/p>\n
[root@fc16 ~]# iptables -L -n -v\r\nChain INPUT (policy ACCEPT 0 packets, 0 bytes)\r\n pkts bytes target     prot opt in     out     source               destination         \r\n14051   10M ACCEPT     all  --  *      *       0.0.0.0\/0            0.0.0.0\/0            state RELATED,ESTABLISHED<\/pre>\n
Netfiler\u76842\u4e2a\u6a21\u5757\uff0cmultiport\u6a21\u5757\u548ciprange\u6a21\u5757\u3002
\nmultiport\u6a21\u5757\u5c06\u5206\u522b\u5bf9\u5e94\u7684\u7aef\u53e3\u6570\u5728\u4e00\u4e2a\u89c4\u5219\u91cc\u8868\u793a\u51fa\u6765\uff0c\u8fd9\u6837\u6bcf\u4e2a\u670d\u52a1\u6240\u9700\u8981\u7684\u5339\u914d\u6570\u90fd\u662f\u4e00\u6837\u7684\u3002
\nIptables -A INPUT -p all -m state \u2013state ESTABLISHED,RELATED -j ACCEPT
\niptables -A INPUT -p tcp \u2013syn -m state NEW \\-m multiport \u2013dports 22,23,25,80,110 -j ACCEPT
\niprange\u6a21\u5757\u662f\u5c06\u89c4\u5219\u4e2d\u7684\u4e00\u6bb5IP\u533a\u57df\u5f00\u653e\uff0c\u4f7f\u7528iprange\u53ef\u4ee5\u7cbe\u7b80\u4e3a\u4e00\u6761\u89c4\u5219
\nIPTABLES -A INPUT -m iprange \u2013src-range \\10.2.20.20-10.2.20.100 -j ACCEPT
\n\u5982\u679c\u9632\u706b\u5899\u540e\u95e8\u6709\u5f88\u591a\u4e3b\u673a\uff0c\u5982\u679c\u6211\u4eec\u5bf9\u4e00\u4e2a\u4e3b\u673a\u914d100\u4e2a\u89c4\u5219\uff0c\u90a3\u4e48\u5c31\u4f1a\u6709300\u4e2a\u89c4\u5219\uff0c\u8fd9\u6837\u5982\u679c\u6709\u4e00\u4e2a\u5c01\u5305\u9700\u8981\u5339\u914d\u6700\u540e\u4e00\u6761\uff0c\u8fd9\u6837\u5c31\u4f1a\u6709299\u6761\u65e0\u6548\u7684\u5339\u914d\u3002\u8fd9\u65f6\u5019\u53ef\u4ee5\u4f7f\u7528User Define Chain\u65b9\u6cd5\u3002User Define Chain\u65b9\u6cd5\u662f\u6307\u7528\u6237\u53ef\u4ee5\u81ea\u5df1\u5b9a\u4e00\u4e2a\u548cINPUT\uff0cFORWORD\uff0cOUTPUT\u4e00\u6837\u7684Chain\u3002
\n\u53ef\u4ee5\u4f7f\u7528iptables \u2014N NAME \u6765\u65b0\u589e\u7b56\u7565\u3002\u5982\u8fc7\u5bf9\u540e\u97623\u4e2a\u4e3b\u673a\u8bbe\u7f6e\u7b56\u7565\uff0c\u6309\u7167IP\u534f\u8bae\u6765\u5206\uff0c\u5c31\u53ef\u4ee5\u5206\u4e3a 10.2.20.160 Chain,10.2.20.161 Chain.\u4ee5\u53ca10.2.20.162Chian.
\n\u5728\u4f18\u5316\u7b56\u7565\u7684\u65f6\u5019\uff0c\u6ca1\u6709\u4e00\u5b9a\u7684\u6807\u51c6\uff0c\u4e5f\u6ca1\u6709\u6b63\u786e\u7684\u7b54\u6848\uff0c\u53ea\u8981\u80fd\u591f\u8ba9\u6574\u4f53\u9632\u706b\u5899\u7684\u65e0\u6548\u5339\u914d\u6b21\u6570\u964d\u5230\u6700\u4f4e\uff0c\u90a3\u4e48\u8fd9\u5c31\u662f\u6211\u4eec\u60f3\u8981\u7684\u3002<\/p>\n
5.1 RAW<\/h3>\n
\u672c\u8282\u5c06\u8bf4\u4e00\u4e0bRAW\u8868\uff0c\u5982\u679c\u7cfb\u7edf\u52a0\u8f7d\u4e86ip_conntrack\u6a21\u5757\uff0c\u4efb\u4f55\u7a7f\u8d8a\u9632\u706b\u5899\u7684\u94fe\u63a5\u90fd\u4f1a\u8bb0\u5f55\u5728\/proc\/net\/ip_conntrack\u6587\u4ef6\u5185\uff0c\u4f46\u6709\u65f6\u5019\uff0c\u6211\u4eec\u4e0d\u4e00\u5b9a\u9700\u8981\u8bb0\u5f55\u6bcf\u4e00\u6761\u94fe\u63a5\u4fe1\u606f\u3002\u5982\u679c\u6211\u4eec\u7684\u89c4\u5219\u5982\u4e0b<\/p>\n
iptables -A FORWORD -i eth1 -o eth2 -m state \u2013-state NEW -j DROP\r\niptables _A FORWORD -i eth2 -o eth1 -m state \u2013-state NEW -j ACCEPT<\/pre>\n
\u8fd9\u65f6\u5019\uff0cip_conntrack\u4f1a\u81ea\u52a8\u8ffd\u8e2a\u6240\u6709\u94fe\u63a5\uff0c\u90a3\u4e48\u6211\u4eec\u600e\u4e48\u8003\u8651\u4e0d\u53bb\u8ffd\u8e2a\u67d0\u4e00\u4e2a\u94fe\u63a5\u5462\uff0cRAW\u5c31\u6d3e\u4e0a\u7528\u573a\u4e86\u3002<\/p>\n
 Iptables -t RAW -A PREROUTING -i eth2 -o eth1 -p tcp --dport 25 -jNOTRACK\r\n Iptables -t RAW -A PREROUTING -i eth1 -o eth2 -p tcp --dport 25 -jNOTRACK<\/pre>\n
RAW table \u6240\u5e26\u6765\u7684\u597d\u5904\u5c31\u662f\u52a0\u901f\uff0c\u4ee5\u53ca\u589e\u52a0\u53ef\u8ffd\u8e2a\u7684\u94fe\u63a5\u6570\u91cf\uff0c\u56e0\u4e3a\u88abRAW Table\u5b9a\u4e49\u7684\u94fe\u63a5\u662f\u4e0d\u4f1a\u88ab\u8ffd\u8e2a\u7684\uff0c\u56e0\u6b64\uff0c\u4e5f\u5c31\u4e0d\u4f1a\u5360\u7528\u4efb\u4f55\u7684\u94fe\u63a5\u8ffd\u8e2a\u6570\u91cf\uff0c\u6b64\u5916\uff0cRAW TABLES \u6240\u5b9a\u4e49\u7684\u94fe\u63a5\u4f1a\u76f4\u63a5\u8df3\u8fc7NAT TABLE \u53ca ip_conntarck\u6a21\u5757\uff0c\u56e0\u6b64\u53ef\u4ee5\u52a0\u901f\u8fdb\u5165\u9632\u706b\u5899\u5c01\u5305\u7684\u901f\u5ea6\uff0c\u4f46\u6240\u5b9a\u4e49\u7684\u94fe\u63a5\u4e5f\u4f1a\u8df3\u8fc7NAT TABLE\uff0c\u6240\u4ee5RAW TABLE\u5b9a\u4e49\u7684\u8fde\u63a5\u90fd\u65e0\u6cd5\u88abNAT \u673a\u5236\u6240\u5904\u7406\u3002
\nRAW TABLE \u62e5\u67092\u4e2aChain\uff0c\u5206\u5e03\u4e3aPREROUTING \uff0cOUTPUT .
\nPREROUTING Chain \u5982\u679c\u662f\u7f51\u5173\u5f0f\u9632\u706b\u5899\uff0c\u5219PREROUTING Chain\u53ef\u4ee5\u7528\u6765\u5904\u7406\u9632\u706b\u5899\u4e24\u4fa7\u7f51\u7edc\u4e4b\u95f4\u6240\u5efa\u7acb\u7684\u94fe\u63a5\uff0c\u56e0\u4e3a\u8fd9\u4e9b\u5c01\u5305\u90fd\u4f1a\u7ecf\u8fc7PRERROUTIN Chain\uff0c\u53e6\u5916\u4e5f\u53ef\u4ee5\u5904\u7406\u4efb\u4f55\u4e3b\u52a8\u94fe\u63a5\u4e3b\u673a\u7684\u8fde\u63a5\u3002
\nOUTPUT Chain \u7c7b\u4f3cNAT TABLE \u7684OUTPUT chain \uff0c\u4f46\u662fPREROUTING Chain\u65e0\u6cd5\u5904\u7406\u4efb\u4f55\u6709\u9632\u706b\u5899\u5bf9\u5916\u5efa\u7acb\u7684\u94fe\u63a5\uff0cRAW \u8bbe\u8ba1\u4e86\u4e00\u4e2aOUTPUT chain\u3002
\n\u9632\u706b\u5899\u7684\u9ad8\u7ea7\u5e94\u7528\u4e3b\u8981\u4e3a\u901a\u4fe1\u534f\u8bae\u7684\u5904\u7406\uff0c\u7b80\u5355\u7684\u534f\u8bae\u548c\u590d\u6742\u7684\u534f\u8bae\uff0c\u5982FTP\uff0cPPTP\uff0cH.323 SIP\u7b49\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
1 \u6982\u8ff0 \u00a0\u9632\u706b\u5899\u7684\u5e94\u7528\u5728linux\u64cd\u4f5c\u7cfb\u7edf\u4e2d\u53ca\u5176…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5],"tags":[61,60,38],"_links":{"self":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/356"}],"collection":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=356"}],"version-history":[{"count":4,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/356\/revisions"}],"predecessor-version":[{"id":360,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=\/wp\/v2\/posts\/356\/revisions\/360"}],"wp:attachment":[{"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=356"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=356"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.selinuxplus.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=356"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}