{"id":241,"date":"2022-04-15T17:15:19","date_gmt":"2022-04-15T09:15:19","guid":{"rendered":"http:\/\/danielw.top\/?p=241"},"modified":"2023-09-22T14:00:36","modified_gmt":"2023-09-22T06:00:36","slug":"tcp%e4%b8%89%e6%ac%a1%e6%8f%a1%e6%89%8b%e5%9b%9b%e6%ac%a1%e6%8c%a5%e6%89%8b","status":"publish","type":"post","link":"http:\/\/danielw.top\/?p=241","title":{"rendered":"TCP\u4e09\u6b21\u63e1\u624b\u56db\u6b21\u6325\u624b"},"content":{"rendered":"<h2>\u5e38\u7528\u7684\u719f\u77e5\u7aef\u53e3\u53f7<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u5e94\u7528\u7a0b\u5e8f<\/th>\n<th>FTP<\/th>\n<th>TFTP<\/th>\n<th>TELNET<\/th>\n<th>SMTP<\/th>\n<th>DNS<\/th>\n<th>HTTP<\/th>\n<th>SSH<\/th>\n<th>MYSQL<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u719f\u77e5\u7aef\u53e3<\/td>\n<td>21,20<\/td>\n<td>69<\/td>\n<td>23<\/td>\n<td>25<\/td>\n<td>53<\/td>\n<td>80<\/td>\n<td>22<\/td>\n<td>3306<\/td>\n<\/tr>\n<tr>\n<td>\u4f20\u8f93\u5c42\u534f\u8bae<\/td>\n<td>TCP<\/td>\n<td>UDP<\/td>\n<td>TCP<\/td>\n<td>TCP<\/td>\n<td>UDP<\/td>\n<td>TCP<\/td>\n<td>TCP<\/td>\n<td>TCP<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>TCP\u7684\u6982\u8ff0<\/h2>\n<p>TCP\u628a\u8fde\u63a5\u4f5c\u4e3a\u6700\u57fa\u672c\u7684\u5bf9\u8c61\uff0c\u6bcf\u4e00\u6761TCP\u8fde\u63a5\u90fd\u6709\u4e24\u4e2a\u7aef\u70b9\uff0c\u8fd9\u79cd\u65ad\u70b9\u6211\u4eec\u53eb\u4f5c\u5957\u63a5\u5b57\uff08socket\uff09\uff0c\u5b83\u7684\u5b9a\u4e49\u4e3a\u7aef\u53e3\u53f7\u62fc\u63a5\u5230IP\u5730\u5740\u5373\u6784\u6210\u4e86\u5957\u63a5\u5b57\uff0c\u4f8b\u5982\uff0c\u82e5IP\u5730\u5740\u4e3a192.3.4.16 \u800c\u7aef\u53e3\u53f7\u4e3a80\uff0c\u90a3\u4e48\u5f97\u5230\u7684\u5957\u63a5\u5b57\u4e3a192.3.4.16:80<\/p>\n<h2>TCP\u62a5\u6587\u9996\u90e8<\/h2>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415161333609.png\" alt=\"image-20220415161333609\" \/><\/p>\n<ol>\n<li>\u6e90\u7aef\u53e3\u548c\u76ee\u7684\u7aef\u53e3\uff0c\u5404\u53602\u4e2a\u5b57\u8282\uff0c\u5206\u522b\u5199\u5165\u6e90\u7aef\u53e3\u548c\u76ee\u7684\u7aef\u53e3\uff1b<\/li>\n<li>\u5e8f\u53f7\uff0c\u53604\u4e2a\u5b57\u8282\uff0cTCP\u8fde\u63a5\u4e2d\u4f20\u9001\u7684\u5b57\u8282\u6d41\u4e2d\u7684\u6bcf\u4e2a\u5b57\u8282\u90fd\u6309\u987a\u5e8f\u7f16\u53f7\u3002\u4f8b\u5982\uff0c\u4e00\u6bb5\u62a5\u6587\u7684\u5e8f\u53f7\u5b57\u6bb5\u503c\u662f 301 \uff0c\u800c\u643a\u5e26\u7684\u6570\u636e\u5171\u6709100\u5b57\u6bb5\uff0c\u663e\u7136\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\uff08\u5982\u679c\u8fd8\u6709\u7684\u8bdd\uff09\u7684\u6570\u636e\u5e8f\u53f7\u5e94\u8be5\u4ece401\u5f00\u59cb\uff1b<\/li>\n<li>\u786e\u8ba4\u53f7\uff0c\u53604\u4e2a\u5b57\u8282\uff0c\u662f\u671f\u671b\u6536\u5230\u5bf9\u65b9\u4e0b\u4e00\u4e2a\u62a5\u6587\u7684\u7b2c\u4e00\u4e2a\u6570\u636e\u5b57\u8282\u7684\u5e8f\u53f7\u3002\u4f8b\u5982\uff0cB\u6536\u5230\u4e86A\u53d1\u9001\u8fc7\u6765\u7684\u62a5\u6587\uff0c\u5176\u5e8f\u5217\u53f7\u5b57\u6bb5\u662f501\uff0c\u800c\u6570\u636e\u957f\u5ea6\u662f200\u5b57\u8282\uff0c\u8fd9\u8868\u660eB\u6b63\u786e\u7684\u6536\u5230\u4e86A\u53d1\u9001\u7684\u5230\u5e8f\u53f7700\u4e3a\u6b62\u7684\u6570\u636e\u3002\u56e0\u6b64\uff0cB\u671f\u671b\u6536\u5230A\u7684\u4e0b\u4e00\u4e2a\u6570\u636e\u5e8f\u53f7\u662f701\uff0c\u4e8e\u662fB\u5728\u53d1\u9001\u7ed9A\u7684\u786e\u8ba4\u62a5\u6587\u6bb5\u4e2d\u628a\u786e\u8ba4\u53f7\u7f6e\u4e3a701\uff1b<\/li>\n<li>\u6570\u636e\u504f\u79fb\uff0c\u53604\u4f4d\uff0c\u5b83\u6307\u51faTCP\u62a5\u6587\u7684\u6570\u636e\u8ddd\u79bbTCP\u62a5\u6587\u6bb5\u7684\u8d77\u59cb\u5904\u6709\u591a\u8fdc\uff1b<\/li>\n<li>\u4fdd\u7559\uff0c\u53606\u4f4d\uff0c\u4fdd\u7559\u4eca\u540e\u4f7f\u7528\uff0c\u4f46\u76ee\u524d\u5e94\u90fd\u4f4d0\uff1b<\/li>\n<li>\u7d27\u6025URG\uff0c\u5f53URG=1\uff0c\u8868\u660e\u7d27\u6025\u6307\u9488\u5b57\u6bb5\u6709\u6548\u3002\u544a\u8bc9\u7cfb\u7edf\u6b64\u62a5\u6587\u6bb5\u4e2d\u6709\u7d27\u6025\u6570\u636e\uff1b<\/li>\n<li>\u786e\u8ba4ACK\uff0c\u4ec5\u5f53ACK=1\u65f6\uff0c\u786e\u8ba4\u53f7\u5b57\u6bb5\u624d\u6709\u6548\u3002TCP\u89c4\u5b9a\uff0c\u5728\u8fde\u63a5\u5efa\u7acb\u540e\u6240\u6709\u62a5\u6587\u7684\u4f20\u8f93\u90fd\u5fc5\u987b\u628aACK\u7f6e1\uff1b<\/li>\n<li>\u63a8\u9001PSH\uff0c\u5f53\u4e24\u4e2a\u5e94\u7528\u8fdb\u7a0b\u8fdb\u884c\u4ea4\u4e92\u5f0f\u901a\u4fe1\u65f6\uff0c\u6709\u65f6\u5728\u4e00\u7aef\u7684\u5e94\u7528\u8fdb\u7a0b\u5e0c\u671b\u5728\u952e\u5165\u4e00\u4e2a\u547d\u4ee4\u540e\u7acb\u5373\u5c31\u80fd\u6536\u5230\u5bf9\u65b9\u7684\u54cd\u5e94\uff0c\u8fd9\u65f6\u5019\u5c31\u5c06PSH=1\uff1b<\/li>\n<li>\u590d\u4f4dRST\uff0c\u5f53RST=1\uff0c\u8868\u660eTCP\u8fde\u63a5\u4e2d\u51fa\u73b0\u4e25\u91cd\u5dee\u9519\uff0c\u5fc5\u987b\u91ca\u653e\u8fde\u63a5\uff0c\u7136\u540e\u518d\u91cd\u65b0\u5efa\u7acb\u8fde\u63a5\uff1b<\/li>\n<li>\u540c\u6b65SYN\uff0c\u5728\u8fde\u63a5\u5efa\u7acb\u65f6\u7528\u6765\u540c\u6b65\u5e8f\u53f7\u3002\u5f53SYN=1\uff0cACK=0\uff0c\u8868\u660e\u662f\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\uff0c\u82e5\u540c\u610f\u8fde\u63a5\uff0c\u5219\u54cd\u5e94\u62a5\u6587\u4e2d\u5e94\u8be5\u4f7fSYN=1\uff0cACK=1\uff1b<\/li>\n<li>\u7ec8\u6b62FIN\uff0c\u7528\u6765\u91ca\u653e\u8fde\u63a5\u3002\u5f53FIN=1\uff0c\u8868\u660e\u6b64\u62a5\u6587\u7684\u53d1\u9001\u65b9\u7684\u6570\u636e\u5df2\u7ecf\u53d1\u9001\u5b8c\u6bd5\uff0c\u5e76\u4e14\u8981\u6c42\u91ca\u653e\uff1b<\/li>\n<li>\u7a97\u53e3\uff0c\u53602\u5b57\u8282\uff0c\u6307\u7684\u662f\u901a\u77e5\u63a5\u6536\u65b9\uff0c\u53d1\u9001\u672c\u62a5\u6587\u4f60\u9700\u8981\u6709\u591a\u5927\u7684\u7a7a\u95f4\u6765\u63a5\u53d7\uff1b<\/li>\n<li>\u68c0\u9a8c\u548c\uff0c\u53602\u5b57\u8282\uff0c\u6821\u9a8c\u9996\u90e8\u548c\u6570\u636e\u8fd9\u4e24\u90e8\u5206\uff1b<\/li>\n<li>\u7d27\u6025\u6307\u9488\uff0c\u53602\u5b57\u8282\uff0c\u6307\u51fa\u672c\u62a5\u6587\u6bb5\u4e2d\u7684\u7d27\u6025\u6570\u636e\u7684\u5b57\u8282\u6570\uff1b<\/li>\n<li>\u9009\u9879\uff0c\u957f\u5ea6\u53ef\u53d8\uff0c\u5b9a\u4e49\u4e00\u4e9b\u5176\u4ed6\u7684\u53ef\u9009\u7684\u53c2\u6570<\/li>\n<\/ol>\n<h2>TCP\u8fde\u63a5\u7684\u5efa\u7acb\uff08<a href=\"https:\/\/so.csdn.net\/so\/search?q=\u4e09\u6b21\u63e1\u624b&amp;spm=1001.2101.3001.7020\" target=\"_blank\"  rel=\"nofollow\" >\u4e09\u6b21\u63e1\u624b<\/a>\uff09<\/h2>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/format,png.png\" alt=\"\u5728\u8fd9\u91cc\u63d2\u5165\u56fe\u7247\u63cf\u8ff0\" \/><\/p>\n<blockquote>\n<p><strong>\u6700\u5f00\u59cb\u7684\u65f6\u5019\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u90fd\u662f\u5904\u4e8eCLOSED\u72b6\u6001\u3002\u4e3b\u52a8\u6253\u5f00\u8fde\u63a5\u7684\u4e3a\u5ba2\u6237\u7aef\uff0c\u88ab\u52a8\u6253\u5f00\u8fde\u63a5\u7684\u662f\u670d\u52a1\u5668\u3002<\/strong><\/p>\n<\/blockquote>\n<ol>\n<li>TCP\u670d\u52a1\u5668\u8fdb\u7a0b\u5148\u521b\u5efa\u4f20\u8f93\u63a7\u5236\u5757TCB\uff0c\u65f6\u523b\u51c6\u5907\u63a5\u53d7\u5ba2\u6237\u8fdb\u7a0b\u7684\u8fde\u63a5\u8bf7\u6c42\uff0c\u6b64\u65f6\u670d\u52a1\u5668\u5c31\u8fdb\u5165\u4e86LISTEN\uff08\u76d1\u542c\uff09\u72b6\u6001\uff1b<\/li>\n<li>TCP\u5ba2\u6237\u8fdb\u7a0b\u4e5f\u662f\u5148\u521b\u5efa\u4f20\u8f93\u63a7\u5236\u5757TCB\uff0c\u7136\u540e\u5411\u670d\u52a1\u5668\u53d1\u51fa\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\uff0c\u8fd9\u662f\u62a5\u6587\u9996\u90e8\u4e2d\u7684\u540c\u90e8\u4f4dSYN=1\uff0c\u540c\u65f6\u9009\u62e9\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7 seq=x \uff0c\u6b64\u65f6\uff0cTCP\u5ba2\u6237\u7aef\u8fdb\u7a0b\u8fdb\u5165\u4e86 SYN-SENT\uff08\u540c\u6b65\u5df2\u53d1\u9001\u72b6\u6001\uff09\u72b6\u6001\u3002TCP\u89c4\u5b9a\uff0cSYN\u62a5\u6587\u6bb5\uff08SYN=1\u7684\u62a5\u6587\u6bb5\uff09\u4e0d\u80fd\u643a\u5e26\u6570\u636e\uff0c\u4f46\u9700\u8981\u6d88\u8017\u6389\u4e00\u4e2a\u5e8f\u53f7\u3002<\/li>\n<li>TCP\u670d\u52a1\u5668\u6536\u5230\u8bf7\u6c42\u62a5\u6587\u540e\uff0c\u5982\u679c\u540c\u610f\u8fde\u63a5\uff0c\u5219\u53d1\u51fa\u786e\u8ba4\u62a5\u6587\u3002\u786e\u8ba4\u62a5\u6587\u4e2d\u5e94\u8be5 ACK=1\uff0cSYN=1\uff0c\u786e\u8ba4\u53f7\u662fack=x+1\uff0c\u540c\u65f6\u4e5f\u8981\u4e3a\u81ea\u5df1\u521d\u59cb\u5316\u4e00\u4e2a\u5e8f\u5217\u53f7 seq=y\uff0c\u6b64\u65f6\uff0cTCP\u670d\u52a1\u5668\u8fdb\u7a0b\u8fdb\u5165\u4e86SYN-RCVD\uff08\u540c\u6b65\u6536\u5230\uff09\u72b6\u6001\u3002\u8fd9\u4e2a\u62a5\u6587\u4e5f\u4e0d\u80fd\u643a\u5e26\u6570\u636e\uff0c\u4f46\u662f\u540c\u6837\u8981\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\u3002<\/li>\n<li>TCP\u5ba2\u6237\u8fdb\u7a0b\u6536\u5230\u786e\u8ba4\u540e\uff0c\u8fd8\u8981\u5411\u670d\u52a1\u5668\u7ed9\u51fa\u786e\u8ba4\u3002\u786e\u8ba4\u62a5\u6587\u7684ACK=1\uff0cack=y+1\uff0c\u81ea\u5df1\u7684\u5e8f\u5217\u53f7seq=x+1\uff0c\u6b64\u65f6\uff0cTCP\u8fde\u63a5\u5efa\u7acb\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165ESTABLISHED\uff08\u5df2\u5efa\u7acb\u8fde\u63a5\uff09\u72b6\u6001\u3002TCP\u89c4\u5b9a\uff0cACK\u62a5\u6587\u6bb5\u53ef\u4ee5\u643a\u5e26\u6570\u636e\uff0c\u4f46\u662f\u5982\u679c\u4e0d\u643a\u5e26\u6570\u636e\u5219\u4e0d\u6d88\u8017\u5e8f\u53f7\u3002<\/li>\n<li>\u5f53\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684\u786e\u8ba4\u540e\u4e5f\u8fdb\u5165ESTABLISHED\u72b6\u6001\uff0c\u6b64\u540e\u53cc\u65b9\u5c31\u53ef\u4ee5\u5f00\u59cb\u901a\u4fe1\u4e86\u3002<\/li>\n<\/ol>\n<h2>\u4f7f\u7528wireshark\u6293\u5305\uff0c\u89c2\u5bdfTCP\u4e09\u6b21\u63e1\u624b<\/h2>\n<p>\u542f\u7528wireshark\u6293\u5305\uff0c\u8bbf\u95ee\u6211\u81ea\u5df1\u7684\u670d\u52a1<\/p>\n<pre><code class=\"language-bash\">curl http:\/\/danielw.top<\/code><\/pre>\n<p>\u8f93\u5165\u8fc7\u6ee4\u6761\u4ef6\u83b7\u53d6\u5f85\u5206\u6790\u6570\u636e\u5305\u5217\u8868<code>ip.addr == 47.118.40.97<\/code><\/p>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415162041752.png\" alt=\"image-20220415162041752\" \/><\/p>\n<p>\u56fe\u4e2d\u53ef\u4ee5\u770b\u5230wireshark\u622a\u83b7\u5230\u4e86\u4e09\u6b21\u63e1\u624b\u7684\u4e09\u4e2a\u6570\u636e\u5305\u3002\u7b2c\u56db\u4e2a\u5305\u624d\u662fHTTP\u7684\uff0c \u8fd9\u8bf4\u660eHTTP\u7684\u786e\u662f\u4f7f\u7528TCP\u5efa\u7acb\u8fde\u63a5\u7684<\/p>\n<h3>\u7b2c\u4e00\u6b21\u63e1\u624b\u6570\u636e\u5305<\/h3>\n<p>\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aTCP\uff0c\u6807\u5fd7\u4f4d\u4e3aSYN\uff0c\u5e8f\u5217\u53f7\u4e3a0\uff0c \u4ee3\u8868\u5ba2\u6237\u7aef\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u3002 \u5982\u4e0b\u56fe<\/p>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415162510330.png\" alt=\"image-20220415162510330\" \/><\/p>\n<p>\u6570\u636e\u5305\u7684\u5173\u952e\u5c5e\u6027\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>SYN \uff1a\u6807\u5fd7\u4f4d\uff0c\u8868\u793a\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5<\/li>\n<li>Seq = 0 \uff1a\u521d\u59cb\u5efa\u7acb\u8fde\u63a5\u503c\u4e3a0\uff0c\u6570\u636e\u5305\u7684\u76f8\u5bf9\u5e8f\u5217\u53f7\u4ece0\u5f00\u59cb\uff0c\u8868\u793a\u5f53\u524d\u8fd8\u6ca1\u6709\u53d1\u9001\u6570\u636e<\/li>\n<li>Ack =0\uff1a\u521d\u59cb\u5efa\u7acb\u8fde\u63a5\u503c\u4e3a0\uff0c\u5df2\u7ecf\u6536\u5230\u5305\u7684\u6570\u91cf\uff0c\u8868\u793a\u5f53\u524d\u6ca1\u6709\u63a5\u6536\u5230\u6570\u636e<\/li>\n<\/ul>\n<h3>\u7b2c\u4e8c\u6b21\u63e1\u624b\u6570\u636e\u5305<\/h3>\n<p>\u670d\u52a1\u5668\u53d1\u56de\u786e\u8ba4\u5305, \u6807\u5fd7\u4f4d\u4e3a SYN,ACK. \u5c06\u786e\u8ba4\u5e8f\u53f7(Acknowledgement Number)\u8bbe\u7f6e\u4e3a\u5ba2\u6237\u7684I S N\u52a01\u4ee5.\u53730+1=1, \u5982\u4e0b\u56fe<\/p>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415163329190.png\" alt=\"image-20220415163329190\" \/><\/p>\n<p>\u6570\u636e\u5305\u7684\u5173\u952e\u5c5e\u6027\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>[SYN+ACK]\uff1a \u6807\u5fd7\u4f4d\uff0c\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u5e76\u56de\u9001SYN\u548cACK<\/li>\n<li>Seq = 0 \uff1a\u521d\u59cb\u5efa\u7acb\u503c\u4e3a0\uff0c\u8868\u793a\u5f53\u524d\u8fd8\u6ca1\u6709\u53d1\u9001\u6570\u636e<\/li>\n<li>Ack = 1\uff1a\u8868\u793a\u5f53\u524d\u7aef\u6210\u529f\u63a5\u6536\u7684\u6570\u636e\u4f4d\u6570\uff0c\u867d\u7136\u5ba2\u6237\u7aef\u6ca1\u6709\u53d1\u9001\u4efb\u4f55\u6709\u6548\u6570\u636e\uff0c\u786e\u8ba4\u53f7\u8fd8\u662f\u88ab\u52a01\uff0c\u56e0\u4e3a\u5305\u542bSYN\u6216FIN\u6807\u5fd7\u4f4d\u3002\uff08\u5e76\u4e0d\u4f1a\u5bf9\u6709\u6548\u6570\u636e\u7684\u8ba1\u6570\u4ea7\u751f\u5f71\u54cd\uff0c\u56e0\u4e3a\u542b\u6709SYN\u6216FIN\u6807\u5fd7\u4f4d\u7684\u5305\u5e76\u4e0d\u643a\u5e26\u6709\u6548\u6570\u636e\uff09<\/li>\n<\/ul>\n<h3>\u7b2c\u4e09\u6b21\u63e1\u624b\u6570\u636e\u5305<\/h3>\n<p>\u5ba2\u6237\u7aef\u518d\u6b21\u53d1\u9001\u786e\u8ba4\u5305(ACK) SYN\u6807\u5fd7\u4f4d\u4e3a0,ACK\u6807\u5fd7\u4f4d\u4e3a1.\u5e76\u4e14\u628a\u670d\u52a1\u5668\u53d1\u6765ACK\u7684\u5e8f\u53f7\u5b57\u6bb5+1,\u653e\u5728\u786e\u5b9a\u5b57\u6bb5\u4e2d\u53d1\u9001\u7ed9\u5bf9\u65b9.\u5e76\u4e14\u5728\u6570\u636e\u6bb5\u653e\u5199ISN\u7684+1, \u5982\u4e0b\u56fe:<\/p>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415164506779.png\" alt=\"image-20220415164506779\" \/><\/p>\n<p>\u6570\u636e\u5305\u7684\u5173\u952e\u5c5e\u6027\u5982\u4e0b\uff1a<\/p>\n<ul>\n<li>ACK \uff1a\u6807\u5fd7\u4f4d\uff0c\u8868\u793a\u5df2\u7ecf\u6536\u5230\u8bb0\u5f55<\/li>\n<li>Seq = 1 \uff1a\u8868\u793a\u5f53\u524d\u5df2\u7ecf\u53d1\u90011\u4e2a\u6570\u636e<\/li>\n<li>Ack = 1 : \u8868\u793a\u5f53\u524d\u7aef\u6210\u529f\u63a5\u6536\u7684\u6570\u636e\u4f4d\u6570\uff0c\u867d\u7136\u670d\u52a1\u7aef\u6ca1\u6709\u53d1\u9001\u4efb\u4f55\u6709\u6548\u6570\u636e\uff0c\u786e\u8ba4\u53f7\u8fd8\u662f\u88ab\u52a01\uff0c\u56e0\u4e3a\u5305\u542bSYN\u6216FIN\u6807\u5fd7\u4f4d\uff08\u5e76\u4e0d\u4f1a\u5bf9\u6709\u6548\u6570\u636e\u7684\u8ba1\u6570\u4ea7\u751f\u5f71\u54cd\uff0c\u56e0\u4e3a\u542b\u6709SYN\u6216FIN\u6807\u5fd7\u4f4d\u7684\u5305\u5e76\u4e0d\u643a\u5e26\u6709\u6548\u6570\u636e)\u3002<\/li>\n<li>\u5c31\u8fd9\u6837\u901a\u8fc7\u4e86TCP\u4e09\u6b21\u63e1\u624b\uff0c\u5efa\u7acb\u4e86\u8fde\u63a5\u3002\u5f00\u59cb\u8fdb\u884c\u6570\u636e\u4ea4\u4e92<\/li>\n<\/ul>\n<h2>TCP\u8fde\u63a5\u7684\u91ca\u653e\uff08\u56db\u6b21\u6325\u624b\uff09<\/h2>\n<p>\u6570\u636e\u4f20\u8f93\u5b8c\u6bd5\u540e\uff0c\u53cc\u65b9\u90fd\u53ef\u91ca\u653e\u8fde\u63a5\u3002\u6700\u5f00\u59cb\u7684\u65f6\u5019\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u90fd\u662f\u5904\u4e8eESTABLISHED\u72b6\u6001\uff0c\u7136\u540e\u5ba2\u6237\u7aef\u4e3b\u52a8\u5173\u95ed\uff0c\u670d\u52a1\u5668\u88ab\u52a8\u5173\u95ed<\/p>\n<ul>\n<li><strong>\u7b2c\u4e00\u6b21\u6325\u624b\uff1a<\/strong><br \/>\n\u670d\u52a1\u7aef\u53d1\u9001\u4e00\u4e2a <code>[FIN+ACK]<\/code> \u62a5\u6587\uff0c\u8868\u793a\u81ea\u5df1\u6ca1\u6709\u6570\u636e\u8981\u53d1\u9001\u4e86\uff0c\u60f3\u65ad\u5f00\u8fde\u63a5\uff0c\u5e76\u8fdb\u5165 <code>fin_wait_1<\/code> \u72b6\u6001\uff08\u4e0d\u80fd\u518d\u53d1\u9001\u6570\u636e\u5230\u5ba2\u6237\u7aef\uff0c\u4f46\u80fd\u591f\u53d1\u9001\u63a7\u5236\u4fe1\u606f <code>ACK<\/code> \u5230\u5ba2\u6237\u7aef\uff09\u3002<\/li>\n<li><strong>\u7b2c\u4e8c\u6b21\u6325\u624b\uff1a<\/strong><br \/>\n\u5ba2\u6237\u7aef\u6536\u5230 <code>[FIN]<\/code> \u62a5\u6587\u540e\uff0c\u5ba2\u6237\u7aef\u77e5\u9053\u4e0d\u4f1a\u518d\u6709\u6570\u636e\u4ece\u670d\u52a1\u7aef\u4f20\u6765\uff0c\u53d1\u9001 <code>ACK<\/code> \u8fdb\u884c\u786e\u8ba4\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165 <code>close_wait<\/code> \u72b6\u6001\u3002\u6b64\u65f6\u670d\u52a1\u7aef\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u5bf9 <code>FIN<\/code> \u7684 <code>ACK<\/code> \u540e\uff0c\u8fdb\u5165 <code>fin_wait2<\/code> \u72b6\u6001\u3002<\/li>\n<li><strong>\u7b2c\u4e09\u6b21\u6325\u624b\uff1a<\/strong><br \/>\n\u5ba2\u6237\u7aef\u53d1\u9001 <code>[FIN ACK]<\/code> \u62a5\u6587\u7ed9\u5bf9\u65b9\uff0c\u8868\u793a\u81ea\u5df1\u6ca1\u6709\u6570\u636e\u8981\u53d1\u9001\u4e86\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165 <code>last_ack<\/code> \u72b6\u6001\u3002\u670d\u52a1\u7aef\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u7684 <code>FIN<\/code> \u4fe1\u4ee4\u540e\uff0c\u8fdb\u5165 <code>time_wait<\/code> \u72b6\u6001\uff0c\u5e76\u53d1\u9001 <code>ACK<\/code> \u786e\u8ba4\u6d88\u606f\u3002<\/li>\n<li><strong>\u7b2c\u56db\u6b21\u6325\u624b\uff1a<\/strong><br \/>\n\u670d\u52a1\u7aef\u5728 <code>time_wait<\/code> \u72b6\u6001\u4e0b\uff0c\u7b49\u5f85 2MSL(MSL\u662f\u6570\u636e\u5206\u8282\u5728\u7f51\u7edc\u4e2d\u5b58\u6d3b\u7684\u6700\u957f\u65f6\u95f4) \u4e00\u6bb5\u65f6\u95f4\uff0c\u6ca1\u6709\u6570\u636e\u5230\u6765\u7684\uff0c\u5c31\u8ba4\u4e3a\u5bf9\u9762\u5df2\u7ecf\u6536\u5230\u4e86\u81ea\u5df1\u53d1\u9001\u7684 <code>ACK<\/code> \u5e76\u6b63\u786e\u5173\u95ed\u4e86\u8fdb\u5165 <code>close<\/code> \u72b6\u6001\uff0c\u81ea\u5df1\u4e5f\u65ad\u5f00\u4e86\u5230\u5ba2\u6237\u7aef\u7684 <code>TCP<\/code> \u8fde\u63a5\uff0c\u91ca\u653e\u6240\u6709\u8d44\u6e90\u3002\u5f53\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u7aef\u7684<code>ACK<\/code> \u56de\u5e94\u540e\uff0c\u4f1a\u8fdb\u5165 <code>close<\/code> \u72b6\u6001\uff0c\u5e76\u5173\u95ed\u672c\u7aef\u7684\u4f1a\u8bdd\u63a5\u53e3\uff0c\u91ca\u653e\u76f8\u5e94\u8d44\u6e90<\/li>\n<\/ul>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/format,png-16500124100969.png\" alt=\"\u56db\u6b21\u6325\u624b\" \/><\/p>\n<h3>\u4e3a\u4ec0\u4e48\u5ba2\u6237\u7aef\u6700\u540e\u8fd8\u8981\u7b49\u5f852MSL\uff1f<\/h3>\n<p>MSL(Maximum Segment Lifetime)\uff1a\u62a5\u6587\u6700\u5927\u751f\u5b58\u65f6\u95f4\uff0c\u5b83\u662f\u4efb\u4f55\u62a5\u6587\u5728\u7f51\u7edc\u4e0a\u5b58\u5728\u7684\u6700\u957f\u65f6\u95f4\uff0c\u8d85\u8fc7\u8fd9\u4e2a\u65f6\u95f4\u62a5\u6587\u5c06\u88ab\u4e22\u5f03\u3002<\/p>\n<p>2MSL\u5373\u4e24\u500d\u7684MSL\uff0cTCP\u7684TIME_WAIT\u72b6\u6001\u4e5f\u79f0\u4e3a2MSL\u7b49\u5f85\u72b6\u6001\uff0c\u5f53TCP\u7684\u4e00\u7aef\u53d1\u8d77\u4e3b\u52a8\u5173\u95ed\uff0c\u5728\u53d1\u51fa\u6700\u540e\u4e00\u4e2aACK\u5305\u540e\u5c31\u8fdb\u5165\u4e86TIME_WAIT\u72b6\u6001\uff0c\u5fc5\u987b\u5728\u6b64\u72b6\u6001\u4e0a\u505c\u7559\u4e24\u500d\u7684MSL\u65f6\u95f4\uff0c\u7b49\u5f852MSL\u65f6\u95f4\u4e3b\u8981\u76ee\u7684\u662f\u6015\u6700\u540e\u4e00\u4e2aACK\u5305\u5bf9\u65b9\u6ca1\u6536\u5230\uff0c\u90a3\u4e48\u5bf9\u65b9\u5728\u8d85\u65f6\u540e\u5c06\u91cd\u53d1\u7b2c\u4e09\u6b21\u63e1\u624b\u7684FIN\u5305\uff0c\u4e3b\u52a8\u5173\u95ed\u7aef\u63a5\u5230\u91cd\u53d1\u7684FIN\u5305\u540e\u53ef\u4ee5\u518d\u53d1\u4e00\u4e2aACK\u5e94\u7b54\u5305<\/p>\n<h3>\u5bf9\u56db\u6b21\u6325\u624b\u8fdb\u884c\u6293\u5305<\/h3>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415171255358-165001403004611.png\" alt=\"image-20220415171255358\" \/><\/p>\n<h3>\u7b2c\u4e00\u6b21\u6325\u624b\u6570\u636e\u5305<\/h3>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415170644132.png\" alt=\"image-20220415170644132\" \/><\/p>\n<h3>\u7b2c\u4e8c\u6b21\u6325\u624b\u6570\u636e\u5305<\/h3>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415170917621.png\" alt=\"image-20220415170917621\" \/><\/p>\n<h3>\u7b2c\u4e09\u6b21\u6325\u624b\u6570\u636e\u5305<\/h3>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415171037932.png\" alt=\"image-20220415171037932\" \/><\/p>\n<h3>\u7b2c\u56db\u6b21\u6325\u624b\u6570\u636e\u5305<\/h3>\n<p><img decoding=\"async\" src=\"http:\/\/img.danielw.top\/image-20220415171111691.png\" alt=\"image-20220415171111691\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5e38\u7528\u7684\u719f\u77e5\u7aef\u53e3\u53f7 \u5e94\u7528\u7a0b\u5e8f FTP TFTP TELNET SMTP DNS HTTP SSH MYSQL \u719f\u77e5\u7aef\u53e3 21,20  &#8230;<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[],"class_list":["post-241","post","type-post","status-publish","format-standard","hentry","category-19"],"_links":{"self":[{"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/posts\/241","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/danielw.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=241"}],"version-history":[{"count":1,"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/posts\/241\/revisions"}],"predecessor-version":[{"id":242,"href":"http:\/\/danielw.top\/index.php?rest_route=\/wp\/v2\/posts\/241\/revisions\/242"}],"wp:attachment":[{"href":"http:\/\/danielw.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=241"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/danielw.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=241"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/danielw.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=241"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}