{"id":156253,"date":"2019-09-04T08:00:55","date_gmt":"2019-09-04T00:00:55","guid":{"rendered":"https:\/\/lrxjmw.cn\/?p=156253"},"modified":"2019-08-21T10:01:20","modified_gmt":"2019-08-21T02:01:20","slug":"tcp-three-communicat","status":"publish","type":"post","link":"https:\/\/lrxjmw.cn\/tcp-three-communicat.html","title":{"rendered":"TCP\u7684\u4e09\u6b21\u63e1\u624b\u4e0e\u56db\u6b21\u6325\u624b"},"content":{"rendered":"<div   id="j6sjwn9j3u"    style=\"font-size: 14pt; color: white; background-color: black; border-left: red 10px solid; padding-left: 14px; margin-bottom: 20px; margin-top: 20px;\"><strong>TCP\u62a5\u6587\u6bb5\u7684\u9996\u90e8\u683c\u5f0f<\/strong><\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-156254\" src=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp1.png\" alt=\"\" width=\"704\" height=\"508\" srcset=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp1.png 704w, https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp1-300x216.png 300w\" sizes=\"auto, (max-width: 704px) 100vw, 704px\" \/><\/p>\n<p><strong>\u5e8f\u5217\u53f7seq\uff1a<\/strong>\u53604\u4e2a\u5b57\u8282\uff0c\u7528\u6765\u6807\u8bb0\u6570\u636e\u6bb5\u7684\u987a\u5e8f\uff0cTCP\u628a\u8fde\u63a5\u4e2d\u53d1\u9001\u7684\u6240\u6709\u6570\u636e\u5b57\u8282\u90fd\u7f16\u4e0a\u4e00\u4e2a\u5e8f\u53f7\uff0c\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7\u7531\u672c\u5730\u968f\u673a\u4ea7\u751f\uff1b\u7ed9\u5b57\u8282\u7f16\u4e0a\u5e8f\u53f7\u540e\uff0c\u5c31\u7ed9\u6bcf\u4e00\u4e2a\u62a5\u6587\u6bb5\u6307\u6d3e\u4e00\u4e2a\u5e8f\u53f7\uff1b\u5e8f\u5217\u53f7seq\u5c31\u662f\u8fd9\u4e2a\u62a5\u6587\u6bb5\u4e2d\u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u6570\u636e\u7f16\u53f7\u3002<\/p>\n<p><strong>\u786e\u8ba4\u53f7ack\uff1a<\/strong>\u53604\u4e2a\u5b57\u8282\uff0c\u671f\u5f85\u6536\u5230\u5bf9\u65b9\u4e0b\u4e00\u4e2a\u62a5\u6587\u6bb5\u7684\u7b2c\u4e00\u4e2a\u6570\u636e\u5b57\u8282\u7684\u5e8f\u53f7\uff1b\u5e8f\u5217\u53f7\u8868\u793a\u62a5\u6587\u6bb5\u643a\u5e26\u6570\u636e\u7684\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7\uff1b\u800c\u786e\u8ba4\u53f7\u6307\u7684\u662f\u671f\u671b\u63a5\u6536\u5230\u4e0b\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7\uff1b\u56e0\u6b64\u5f53\u524d\u62a5\u6587\u6bb5\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u7684\u7f16\u53f7+1\u5373\u4e3a\u786e\u8ba4\u53f7\u3002<\/p>\n<p><strong>\u786e\u8ba4ACK\uff1a<\/strong>\u53601\u4f4d\uff0c\u4ec5\u5f53ACK=1\u65f6\uff0c\u786e\u8ba4\u53f7\u5b57\u6bb5\u624d\u6709\u6548\u3002ACK=0\u65f6\uff0c\u786e\u8ba4\u53f7\u65e0\u6548\u3002TCP\u89c4\u5b9a\uff0c\u5728\u8fde\u63a5\u5efa\u7acb\u540e\u6240\u6709\u4f20\u9001\u7684\u62a5\u6587\u6bb5\u90fd\u5fc5\u987b\u628aACK\u7f6e\u4e3a1\u3002<\/p>\n<p><strong>\u540c\u6b65SYN\uff1a<\/strong>\u8fde\u63a5\u5efa\u7acb\u65f6\u7528\u4e8e\u540c\u6b65\u5e8f\u53f7\u3002\u5f53SYN=1\uff0cACK=0\u65f6\u8868\u793a\uff1a\u8fd9\u662f\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\u62a5\u6587\u6bb5\u3002\u82e5\u540c\u610f\u8fde\u63a5\uff0c\u5219\u5728\u54cd\u5e94\u62a5\u6587\u6bb5\u4e2d\u4f7f\u5f97SYN=1\uff0cACK=1\u3002\u56e0\u6b64\uff0cSYN=1\u8868\u793a\u8fd9\u662f\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\uff0c\u6216\u8fde\u63a5\u63a5\u53d7\u62a5\u6587\u3002SYN\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u53ea\u6709\u5728TCP\u5efa\u4ea7\u8fde\u63a5\u65f6\u624d\u4f1a\u88ab\u7f6e1\uff0c\u63e1\u624b\u5b8c\u6210\u540eSYN\u6807\u5fd7\u4f4d\u88ab\u7f6e0\u3002<\/p>\n<p><strong>\u7ec8\u6b62FIN\uff1a<\/strong>\u7528\u6765\u91ca\u653e\u4e00\u4e2a\u8fde\u63a5\u3002FIN=1\u8868\u793a\uff1a\u6b64\u62a5\u6587\u6bb5\u7684\u53d1\u9001\u65b9\u7684\u6570\u636e\u5df2\u7ecf\u53d1\u9001\u5b8c\u6bd5\uff0c\u5e76\u8981\u6c42\u91ca\u653e\u8fd0\u8f93\u8fde\u63a5<\/p>\n<p><strong>PS\uff1a<\/strong>ACK\u3001SYN\u548cFIN\u8fd9\u4e9b\u5927\u5199\u7684\u5355\u8bcd\u8868\u793a\u6807\u5fd7\u4f4d\uff0c\u5176\u503c\u8981\u4e48\u662f1\uff0c\u8981\u4e48\u662f0\uff1back\u3001seq\u5c0f\u5199\u7684\u5355\u8bcd\u8868\u793a\u5e8f\u53f7\u3002<\/p>\n<table>\n<thead>\n<tr class=\"header\">\n<th>\u5b57\u6bb5<\/th>\n<th>\u542b\u4e49<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr class=\"odd\">\n<td>URG<\/td>\n<td>\u7d27\u6025\u6307\u9488\u662f\u5426\u6709\u6548\u3002\u4e3a1\uff0c\u8868\u793a\u67d0\u4e00\u4f4d\u9700\u8981\u88ab\u4f18\u5148\u5904\u7406<\/td>\n<\/tr>\n<tr class=\"even\">\n<td>ACK<\/td>\n<td>\u786e\u8ba4\u53f7\u662f\u5426\u6709\u6548\uff0c\u4e00\u822c\u7f6e\u4e3a1\u3002<\/td>\n<\/tr>\n<tr class=\"odd\">\n<td>PSH<\/td>\n<td>\u63d0\u793a\u63a5\u6536\u7aef\u5e94\u7528\u7a0b\u5e8f\u7acb\u5373\u4eceTCP\u7f13\u51b2\u533a\u628a\u6570\u636e\u8bfb\u8d70\u3002<\/td>\n<\/tr>\n<tr class=\"even\">\n<td>RST<\/td>\n<td>\u5bf9\u65b9\u8981\u6c42\u91cd\u65b0\u5efa\u7acb\u8fde\u63a5\uff0c\u590d\u4f4d\u3002<\/td>\n<\/tr>\n<tr class=\"odd\">\n<td>SYN<\/td>\n<td>\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\uff0c\u5e76\u5728\u5176\u5e8f\u5217\u53f7\u7684\u5b57\u6bb5\u8fdb\u884c\u5e8f\u5217\u53f7\u7684\u521d\u59cb\u503c\u8bbe\u5b9a\u3002\u5efa\u7acb\u8fde\u63a5\uff0c\u8bbe\u7f6e\u4e3a1<\/td>\n<\/tr>\n<tr class=\"even\">\n<td>FIN<\/td>\n<td>\u5e0c\u671b\u65ad\u5f00\u8fde\u63a5\u3002<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<div   id="j6sjwn9j3u"    style=\"font-size: 14pt; color: white; background-color: black; border-left: red 10px solid; padding-left: 14px; margin-bottom: 20px; margin-top: 20px;\"><strong>TCP\u4e09\u6b21\u63e1\u624b<\/strong><\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-156255\" src=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp2.png\" alt=\"\" width=\"636\" height=\"369\" srcset=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp2.png 636w, https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp2-300x174.png 300w\" sizes=\"auto, (max-width: 636px) 100vw, 636px\" \/><\/p>\n<p><strong>\u7b2c\u4e00\u6b21\u63e1\u624b\uff1a<\/strong>\u5efa\u7acb\u8fde\u63a5\u65f6\uff0c\u5ba2\u6237\u7aef\u53d1\u9001syn\u5305\uff08syn=j\uff09\u5230\u670d\u52a1\u5668\uff0c\u5e76\u8fdb\u5165SYN_SENT\u72b6\u6001\uff0c\u7b49\u5f85\u670d\u52a1\u5668\u786e\u8ba4\uff1bSYN\uff1a\u540c\u6b65\u5e8f\u5217\u7f16\u53f7\uff08Synchronize Sequence Numbers\uff09\u3002<\/p>\n<p><strong>\u7b2c\u4e8c\u6b21\u63e1\u624b\uff1a<\/strong>\u670d\u52a1\u5668\u6536\u5230syn\u5305\uff0c\u5fc5\u987b\u786e\u8ba4\u5ba2\u6237\u7684SYN\uff08ack=j+1\uff09\uff0c\u540c\u65f6\u81ea\u5df1\u4e5f\u53d1\u9001\u4e00\u4e2aSYN\u5305\uff08syn=k\uff09\uff0c\u5373SYN+ACK\u5305\uff0c\u6b64\u65f6\u670d\u52a1\u5668\u8fdb\u5165SYN_RECV\u72b6\u6001\uff1b<\/p>\n<p><strong>\u7b2c\u4e09\u6b21\u63e1\u624b\uff1a<\/strong>\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684SYN+ACK\u5305\uff0c\u5411\u670d\u52a1\u5668\u53d1\u9001\u786e\u8ba4\u5305ACK(ack=k+1\uff09\uff0c\u6b64\u5305\u53d1\u9001\u5b8c\u6bd5\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u8fdb\u5165ESTABLISHED\uff08TCP\u8fde\u63a5\u6210\u529f\uff09\u72b6\u6001\uff0c\u5b8c\u6210\u4e09\u6b21\u63e1\u624b<\/p>\n<div   id="j6sjwn9j3u"    style=\"font-size: 14pt; color: white; background-color: black; border-left: red 10px solid; padding-left: 14px; margin-bottom: 20px; margin-top: 20px;\"><strong>TCP\u56db\u6b21\u6325\u624b<\/strong><\/div>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter size-full wp-image-156256\" src=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp3.png\" alt=\"\" width=\"624\" height=\"384\" srcset=\"https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp3.png 624w, https:\/\/lrxjmw.cn\/wp-content\/uploads\/2019\/08\/tcp3-300x185.png 300w\" sizes=\"auto, (max-width: 624px) 100vw, 624px\" \/><\/p>\n<p>1\uff09\u5ba2\u6237\u7aef\u8fdb\u7a0b\u53d1\u51fa\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff0c\u5e76\u4e14\u505c\u6b62\u53d1\u9001\u6570\u636e\u3002\u91ca\u653e\u6570\u636e\u62a5\u6587\u9996\u90e8\uff0cFIN=1\uff0c\u5176\u5e8f\u5217\u53f7\u4e3aseq=u\uff08\u7b49\u4e8e\u524d\u9762\u5df2\u7ecf\u4f20\u9001\u8fc7\u6765\u7684\u6570\u636e\u7684\u6700\u540e\u4e00\u4e2a\u5b57\u8282\u7684\u5e8f\u53f7\u52a01\uff09\uff0c\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165FIN-WAIT-1\uff08\u7ec8\u6b62\u7b49\u5f851\uff09\u72b6\u6001\u3002 TCP\u89c4\u5b9a\uff0cFIN\u62a5\u6587\u6bb5\u5373\u4f7f\u4e0d\u643a\u5e26\u6570\u636e\uff0c\u4e5f\u8981\u6d88\u8017\u4e00\u4e2a\u5e8f\u53f7\u3002<\/p>\n<p>2\uff09\u670d\u52a1\u5668\u6536\u5230\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff0c\u53d1\u51fa\u786e\u8ba4\u62a5\u6587\uff0cACK=1\uff0cack=u+1\uff0c\u5e76\u4e14\u5e26\u4e0a\u81ea\u5df1\u7684\u5e8f\u5217\u53f7seq=v\uff0c\u6b64\u65f6\uff0c\u670d\u52a1\u7aef\u5c31\u8fdb\u5165\u4e86CLOSE-WAIT\uff08\u5173\u95ed\u7b49\u5f85\uff09\u72b6\u6001\u3002TCP\u670d\u52a1\u5668\u901a\u77e5\u9ad8\u5c42\u7684\u5e94\u7528\u8fdb\u7a0b\uff0c\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u7684\u65b9\u5411\u5c31\u91ca\u653e\u4e86\uff0c\u8fd9\u65f6\u5019\u5904\u4e8e\u534a\u5173\u95ed\u72b6\u6001\uff0c\u5373\u5ba2\u6237\u7aef\u5df2\u7ecf\u6ca1\u6709\u6570\u636e\u8981\u53d1\u9001\u4e86\uff0c\u4f46\u662f\u670d\u52a1\u5668\u82e5\u53d1\u9001\u6570\u636e\uff0c\u5ba2\u6237\u7aef\u4f9d\u7136\u8981\u63a5\u53d7\u3002\u8fd9\u4e2a\u72b6\u6001\u8fd8\u8981\u6301\u7eed\u4e00\u6bb5\u65f6\u95f4\uff0c\u4e5f\u5c31\u662f\u6574\u4e2aCLOSE-WAIT\u72b6\u6001\u6301\u7eed\u7684\u65f6\u95f4\u3002<\/p>\n<p>3\uff09\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684\u786e\u8ba4\u8bf7\u6c42\u540e\uff0c\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u5c31\u8fdb\u5165FIN-WAIT-2\uff08\u7ec8\u6b62\u7b49\u5f852\uff09\u72b6\u6001\uff0c\u7b49\u5f85\u670d\u52a1\u5668\u53d1\u9001\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff08\u5728\u8fd9\u4e4b\u524d\u8fd8\u9700\u8981\u63a5\u53d7\u670d\u52a1\u5668\u53d1\u9001\u7684\u6700\u540e\u7684\u6570\u636e\uff09\u3002<\/p>\n<p>4\uff09\u670d\u52a1\u5668\u5c06\u6700\u540e\u7684\u6570\u636e\u53d1\u9001\u5b8c\u6bd5\u540e\uff0c\u5c31\u5411\u5ba2\u6237\u7aef\u53d1\u9001\u8fde\u63a5\u91ca\u653e\u62a5\u6587\uff0cFIN=1\uff0cack=u+1\uff0c\u7531\u4e8e\u5728\u534a\u5173\u95ed\u72b6\u6001\uff0c\u670d\u52a1\u5668\u5f88\u53ef\u80fd\u53c8\u53d1\u9001\u4e86\u4e00\u4e9b\u6570\u636e\uff0c\u5047\u5b9a\u6b64\u65f6\u7684\u5e8f\u5217\u53f7\u4e3aseq=w\uff0c\u6b64\u65f6\uff0c\u670d\u52a1\u5668\u5c31\u8fdb\u5165\u4e86LAST-ACK\uff08\u6700\u540e\u786e\u8ba4\uff09\u72b6\u6001\uff0c\u7b49\u5f85\u5ba2\u6237\u7aef\u7684\u786e\u8ba4\u3002<\/p>\n<p>5\uff09\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684\u8fde\u63a5\u91ca\u653e\u62a5\u6587\u540e\uff0c\u5fc5\u987b\u53d1\u51fa\u786e\u8ba4\uff0cACK=1\uff0cack=w+1\uff0c\u800c\u81ea\u5df1\u7684\u5e8f\u5217\u53f7\u662fseq=u+1\uff0c\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u5c31\u8fdb\u5165\u4e86TIME-WAIT\uff08\u65f6\u95f4\u7b49\u5f85\uff09\u72b6\u6001\u3002\u6ce8\u610f\u6b64\u65f6TCP\u8fde\u63a5\u8fd8\u6ca1\u6709\u91ca\u653e\uff0c\u5fc5\u987b\u7ecf\u8fc72\u2217\u2217MSL\uff08\u6700\u957f\u62a5\u6587\u6bb5\u5bff\u547d\uff09\u7684\u65f6\u95f4\u540e\uff0c\u5f53\u5ba2\u6237\u7aef\u64a4\u9500\u76f8\u5e94\u7684TCB\u540e\uff0c\u624d\u8fdb\u5165CLOSED\u72b6\u6001\u3002<\/p>\n<p>6\uff09\u670d\u52a1\u5668\u53ea\u8981\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u53d1\u51fa\u7684\u786e\u8ba4\uff0c\u7acb\u5373\u8fdb\u5165CLOSED\u72b6\u6001\u3002\u540c\u6837\uff0c\u64a4\u9500TCB\u540e\uff0c\u5c31\u7ed3\u675f\u4e86\u8fd9\u6b21\u7684TCP\u8fde\u63a5\u3002\u53ef\u4ee5\u770b\u5230\uff0c\u670d\u52a1\u5668\u7ed3\u675fTCP\u8fde\u63a5\u7684\u65f6\u95f4\u8981\u6bd4\u5ba2\u6237\u7aef\u65e9\u4e00\u4e9b\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5e8f\u5217\u53f7seq\uff1a\u53604\u4e2a\u5b57\u8282\uff0c\u7528\u6765\u6807\u8bb0\u6570\u636e\u6bb5\u7684\u987a\u5e8f\uff0cTCP\u628a\u8fde\u63a5\u4e2d\u53d1\u9001\u7684\u6240\u6709\u6570\u636e\u5b57\u8282\u90fd\u7f16\u4e0a\u4e00\u4e2a\u5e8f\u53f7\uff0c\u7b2c\u4e00\u4e2a\u5b57\u8282\u7684\u7f16 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