{"id":347,"date":"2023-11-26T21:11:00","date_gmt":"2023-11-26T13:11:00","guid":{"rendered":"http:\/\/8.141.4.74\/?p=347"},"modified":"2024-03-28T13:43:07","modified_gmt":"2024-03-28T05:43:07","slug":"tcp%e8%bf%9e%e6%8e%a5%e7%9a%84%e7%94%9f%e5%91%bd%e5%91%a8%e6%9c%9f%ef%bc%9a%e6%b7%b1%e7%a9%b6%e4%b8%89%e6%ac%a1%e6%8f%a1%e6%89%8b%e4%b8%8e%e5%9b%9b%e6%ac%a1%e6%8c%a5%e6%89%8b%e6%9c%ba%e5%88%b6","status":"publish","type":"post","link":"http:\/\/8.141.4.74\/?p=347","title":{"rendered":"TCP\u8fde\u63a5\u7684\u751f\u547d\u5468\u671f\uff1a\u6df1\u7a76\u4e09\u6b21\u63e1\u624b\u4e0e\u56db\u6b21\u6325\u624b\u673a\u5236"},"content":{"rendered":"

TCP\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b<\/h1>\n
\n

TCP\uff08Transmission Control Protocol\uff09\u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u3001\u57fa\u4e8e\u5b57\u8282\u6d41\u7684\u4f20\u8f93\u5c42\u901a\u4fe1\u534f\u8bae\uff0c\u7528\u4e8e\u5728\u7f51\u7edc\u4e0a\u5efa\u7acb\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u901a\u9053\u3002\u5728TCP\/IP\u534f\u8bae\u65cf\u4e2d\uff0cTCP\u8d1f\u8d23\u5728\u6570\u636e\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u63d0\u4f9b\u53ef\u9760\u6027\u548c\u5b8c\u6574\u6027\u4fdd\u8bc1\u3002TCP\u534f\u8bae\u4e2d\u7684\u4e09\u6b21\u63e1\u624b\u548c\u56db\u6b21\u6325\u624b\u662f\u5efa\u7acb\u548c\u7ec8\u6b62TCP\u8fde\u63a5\u65f6\u5fc5\u987b\u7ecf\u8fc7\u7684\u8fc7\u7a0b\u3002<\/p>\n<\/blockquote>\n

TCP\u4e09\u6b21\u63e1\u624b<\/h2>\n
\n

TCP\u4e09\u6b21\u63e1\u624b\u662f\u5efa\u7acbTCP\u8fde\u63a5\u7684\u8fc7\u7a0b\uff0c\u901a\u8fc7\u4e09\u6b21\u63e1\u624b\uff0c\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u53ef\u4ee5\u5efa\u7acb\u4e00\u4e2a\u53ef\u9760\u7684\u8fde\u63a5\uff0c\u786e\u4fdd\u6570\u636e\u80fd\u591f\u5b89\u5168\u53ef\u9760\u5730\u4f20\u8f93\u3002<\/p>\n<\/blockquote>\n

TCP\u4e09\u6b21\u63e1\u624b\u662fTCP\u534f\u8bae\u7528\u4e8e\u5efa\u7acb\u53ef\u9760\u8fde\u63a5\u7684\u8fc7\u7a0b\u3002\u4ee5\u4e0b\u662fTCP\u4e09\u6b21\u63e1\u624b\u7684\u8be6\u7ec6\u6b65\u9aa4\uff1a<\/p>\n

    \n
  1. \u7b2c\u4e00\u6b21\u63e1\u624b\uff08SYN\uff0c\u540c\u6b65\u5e8f\u5217\u7f16\u53f7\uff09\uff1a<\/li>\n<\/ol>\n

    \u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\uff0c\u53d1\u9001\u4e00\u4e2aTCP\u6570\u636e\u5305\uff0c\u5176\u4e2d\u8bbe\u7f6e\u4e86SYN\u6807\u5fd7\u4f4d\uff08\u7f6e\u4e3a1\uff09\uff0c\u540c\u65f6\u4e3a\u8be5\u8fde\u63a5\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u7684\u5e8f\u5217\u53f7\uff08ISN\uff0c\u968f\u673a\u6570\uff0c\u8bb0\u4e3aX\uff09\u3002\u8fd9\u4e00\u8fc7\u7a0b\u88ab\u79f0\u4e3a\u7b2c\u4e00\u6b21\u63e1\u624b\u3002\uff08\u6216\u8005\u8bf4\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\uff08SYN = Synchronize Sequence Numbers\uff09\uff0c\u5176\u4e2dSYN\u6807\u5fd7\u4f4d\u88ab\u7f6e\u4e3a1\uff0c\u5176\u4e2d\u5305\u542b\u81ea\u5df1\u7684\u968f\u673a\u521d\u59cb\u5e8f\u5217\u53f7\uff08ISN\uff09,\u5e76\u4e14\u8be5\u62a5\u6587\u6bb5\u4e0d\u5305\u542b\u6570\u636e\uff0c\u8868\u793a\u53d1\u9001\u65b9\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u3002\uff09<\/p>\n

      \n
    1. \u7b2c\u4e8c\u6b21\u63e1\u624b\uff08SYN+ACK\uff0c\u786e\u8ba4\uff09\uff1a<\/li>\n<\/ol>\n

      \u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684\u8fde\u63a5\u8bf7\u6c42\u540e\uff0c\u5982\u679c\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u4f1a\u5411\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aTCP\u6570\u636e\u5305\u3002\u8fd9\u4e2a\u6570\u636e\u5305\uff0cSYN\u548cACK\u6807\u5fd7\u4f4d\u90fd\u88ab\u8bbe\u7f6e\u4e3a1.\u670d\u52a1\u5668\u4e5f\u4f1a\u4e3a\u6b64\u8fde\u63a5\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff08\u968f\u673a\u6570\uff0c\u8bb0\u4e3aY\uff09\uff0c\u540c\u65f6\u5c06\u5ba2\u6237\u7aef\u53d1\u6765\u7684\u5e8f\u5217\u53f7X\u52a01\uff08\u5373X+1\uff09\uff0c\u4f5c\u4e3a\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u53d1\u9001\u7ed9\u5ba2\u6237\u7aef\uff0c\u8fd9\u4e00\u8fc7\u7a0b\u88ab\u79f0\u4e3a\u7b2c\u4e8c\u6b21\u63e1\u624b\u3002\uff08\u6216\u8005\u8bf4\u670d\u52a1\u5668\u63a5\u6536\u5230\u5ba2\u6237\u7aef\u7684SYN\u62a5\u6587\u6bb5\u540e\uff0c\u8fd4\u56de\u4e00\u4e2aSYN+ACK\uff08\u540c\u6b65\u5e8f\u5217\u7f16\u53f7+\u786e\u8ba4\u5e8f\u5217\u7f16\u53f7\uff09\u62a5\u6587\u6bb5\uff0c\u5176\u4e2d\u786e\u8ba4\u5e8f\u5217\u53f7\u4e3a\u5ba2\u6237\u7aef\u7684SIN+1\uff0c\u540c\u65f6\u4e5f\u5305\u542b\u81ea\u5df1\u7684\u521d\u59cb\u7cfb\u5217\u53f7\uff08ISN\uff09\uff0c\u8be5\u62a5\u6587\u6bb5\u4e2dSYN\u548cACK\u6807\u5fd7\u4f4d\u90fd\u88ab\u7f6e\u4e3a1\uff0c\u8868\u793a\u786e\u8ba4\u5efa\u7acb\u8fde\u63a5\uff0c\u5e76\u4e14\u8be5\u62a5\u6587\u6bb5\u4e5f\u5305\u542b\u6570\u636e\u3002\uff09\uff08SYN+ACK=Synchronize Acknowledgement\uff09<\/p>\n

      \u5b9e\u9645\u4e0a\uff0cACK = 1 \u662f\u4e00\u4e2a\u6807\u5fd7\u4f4d\uff0c\u8868\u793a\u6570\u636e\u5305\u4e2d\u5305\u542b\u4e00\u4e2a\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u3002\u5f53ACK\u6807\u5fd7\u4f4d\u4e3a1\u65f6\uff0c\u624d\u9700\u8981\u68c0\u67e5\u786e\u8ba4\u53f7\u3002<\/p>\n

        \n
      1. \u7b2c\u4e09\u6b21\u63e1\u624b\uff08ACK\uff09\uff1a<\/li>\n<\/ol>\n

        \u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684SYN+ACK\u6570\u636e\u5305\u540e\uff0c\u4f1a\u68c0\u67e5\u5176\u4e2d\u7684ACK\u6807\u5fd7\u4f4d\u548c\u786e\u8ba4\u53f7\u662f\u5426\u6b63\u786e\u3002\u5982\u679c\u786e\u8ba4\u53f7\u662f\u81ea\u5df1\u53d1\u9001\u7684\u5e8f\u5217\u53f7X\u52a01\uff0c\u8bf4\u660e\u670d\u52a1\u5668\u5df2\u7ecf\u6b63\u786e\u63a5\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u7684\u8bf7\u6c42\u3002\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u4f1a\u53d1\u9001\u4e00\u4e2aACK\u6570\u636e\u5305\uff0c\u5176\u4e2dACK\u6807\u5fd7\u4f4d\u4e3a1\uff0c\u786e\u8ba4\u53f7\u4e3a\u670d\u52a1\u5668\u53d1\u9001\u7684\u5e8f\u5217\u53f7Y\u52a01\uff08\u5373Y+1\uff09\u3002\u670d\u52a1\u5668\u6536\u5230\u8fd9\u4e2aACK\u6570\u636e\u5305\u540e\uff0c\u5c31\u786e\u8ba4\u5ba2\u6237\u7aef\u4e5f\u5df2\u7ecf\u6536\u5230\u4e86\u81ea\u5df1\u7684\u56de\u5e94\u3002\u8fd9\u4e00\u8fc7\u7a0b\u88ab\u79f0\u4e3a\u7b2c\u4e09\u6b21\u63e1\u624b\u3002\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684SYN-ACK\u62a5\u6587\u6bb5\u540e\uff0c\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001\u4e00\u4e2aACK\uff08\u786e\u8ba4\uff09\u62a5\u6587\u6bb5\uff08ACK=Acknowledge\uff09\u3002\u8be5\u62a5\u6587\u6bb5\u4e2dACK\u6807\u5fd7\u4f4d\u88ab\u7f6e\u4e3a1\uff0c\u8868\u793a\u5ba2\u6237\u7aef\u5df2\u7ecf\u6536\u5230\u4e86\u670d\u52a1\u5668\u7684SYN-ACK\u62a5\u6587\u6bb5\uff0c\u5e76\u5411\u670d\u52a1\u5668\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u3002\u6b64\u65f6\uff0cTCP\u8fde\u63a5\u5efa\u7acb\u6210\u529f\uff0c\u53ef\u4ee5\u8fdb\u884c\u6570\u636e\u4f20\u8f93\u3002<\/p>\n

        TCP\u4e09\u6b21\u63e1\u624b\u7684\u8fc7\u7a0b\u4fdd\u8bc1\u4e86\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u4e4b\u95f4\u7684\u8fde\u63a5\u662f\u53ef\u9760\u7684\uff0c\u5e76\u4e14\u53cc\u65b9\u90fd\u540c\u610f\u5efa\u7acb\u8fde\u63a5\u3002\u8fd9\u4e5f\u662fTCP\u534f\u8bae\u6210\u4e3a\u53ef\u9760\u4f20\u8f93\u534f\u8bae\u7684\u91cd\u8981\u539f\u56e0\u4e4b\u4e00\u3002<\/p>\n

        ISN\uff08Initial Sequence Numbers\uff0c\u521d\u59cb\u5e8f\u5217\u53f7\uff09\u662fTCP\u8fde\u63a5\u5efa\u7acb\u8fc7\u7a0b\u4e2d\u7684\u4e00\u4e2a\u6982\u5ff5\u3002\u5728TCP\u534f\u8bae\u4e2d\uff0c\u6bcf\u4e2a\u6570\u636e\u5305\u90fd\u6709\u4e00\u4e2a\u5e8f\u5217\u53f7\uff0c\u7528\u4e8e\u8868\u793a\u8be5\u6570\u636e\u5305\u5728\u6570\u636e\u6d41\u4e2d\u7684\u4f4d\u7f6e\u3002\u5f53\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u5efa\u7acb\u8fde\u63a5\u65f6\uff0c\u5b83\u4eec\u5404\u81ea\u4e3a\u8fd9\u4e2a\u8fde\u63a5\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff0c\u5373\u6240\u8c13\u7684ISN\u3002<\/p>\n

        \u5728\u4e0a\u9762\u7684\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\uff0c\u6211\u4eec\u63d0\u5230\u4e86\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u5206\u522b\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff08\u968f\u673a\u6570\uff0c\u5206\u522b\u8bb0\u4e3aX\u548cY\uff09\u3002\u8fd9\u4e24\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\u5b9e\u9645\u4e0a\u5c31\u662f\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u7684ISN\u3002\u8fd9\u4e9b\u968f\u673a\u6570\u7528\u4e8e\u786e\u4fdd\u6bcf\u4e00\u4e2aTCP\u8fde\u63a5\u7684\u552f\u4e00\u6027\uff0c\u4ee5\u53ca\u9632\u6b62\u91cd\u590d\u548c\u5931\u6548\u7684\u6570\u636e\u5305\u88ab\u9519\u8bef\u5730\u63a5\u6536\u3002<\/p>\n

        \u5728\u4e09\u6b21\u63e1\u624b\u7684\u8fc7\u7a0b\u4e2d\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u4f1a\u4ea4\u6362\u5b83\u4eec\u7684ISN\uff0c\u5e76\u5728\u786e\u8ba4\u5bf9\u65b9\u63a5\u6536\u5230\u6570\u636e\u5305\u540e\uff0c\u5c06\u5e8f\u5217\u53f7\u52a01\uff0c\u4f5c\u4e3a\u786e\u8ba4\u53f7\u3002\u8fd9\u6837\uff0c\u53cc\u65b9\u5c31\u53ef\u4ee5\u6839\u636e\u6d59\u897f\u997f\u5e8f\u5217\u53f7\u6765\u8ffd\u8e2a\u6570\u636e\u6d41\u7684\u987a\u5e8f\u548c\u5b8c\u6574\u6027\u3002<\/p>\n

        \u8ba9\u6211\u4eec\u91cd\u65b0\u5ba1\u89c6\u4e09\u6b21\u63e1\u624b\u7684\u8fc7\u7a0b\uff1a<\/p>\n

          \n
        1. \u5ba2\u6237\u7aef\u53d1\u9001SYN\u6570\u636e\u5305\uff0c\u5176\u4e2dSYN = 1\uff0c\u540c\u65f6\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff08ISN\uff0c\u8bb0\u4e3aX\uff09\u3002<\/li>\n
        2. \u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684\u8fde\u63a5\u8bf7\u6c42\u540e\uff0c\u53d1\u9001\u4e00\u4e2aSYN+ACK\u6570\u636e\u5305\u3002\u5176\u4e2d\uff0cSYN = 1\uff0cACK = 1\u3002\u540c\u65f6\uff0c\u670d\u52a1\u5668\u751f\u6210\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff08\u8bb0\u4e3aY\uff09\uff0c\u5e76\u5c06\u5ba2\u6237\u7aef\u7684\u5e8f\u5217\u53f7\u52a01\uff08\u5373X+1\uff09\uff0c\u4f5c\u4e3a\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u3002<\/li>\n
        3. \u5ba2\u6237\u7aef\u6536\u5230SYN+ACK\u6570\u636e\u5305\u540e\uff0c\u68c0\u67e5\u5176\u4e2d\u7684ACK\u6807\u5fd7\u4f4d\uff08\u5e94\u4e3a1\uff09\uff0c\u5e76\u68c0\u67e5\u786e\u8ba4\u53f7\uff08\u5e94\u4e3aX+1\uff09\u3002\u786e\u8ba4\u65e0\u8bef\u540e\uff0c\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aACK\u6570\u636e\u5305\uff0c\u5176\u4e2dACK = 1\uff0c\u786e\u8ba4\u53f7\u4e3aY+1\u3002<\/li>\n<\/ol>\n

          \u5728\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u4f7f\u7528X+1\u4f5c\u4e3a\u670d\u52a1\u5668\u54cd\u5e94\u4e2d\u7684\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u662f\u4e3a\u4e86\u786e\u4fdd\u670d\u52a1\u5668\u6b63\u786e\u63a5\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u7684\u8fde\u63a5\u8bf7\u6c42\u3002\u5f53\u5ba2\u6237\u7aef\u68c0\u67e5\u5230\u786e\u8ba4\u53f7\u4e3aX+1\u65f6\uff0c\u8bf4\u660e\u670d\u52a1\u5668\u786e\u5b9e\u6536\u5230\u4e86\u521d\u59cb\u7684SYN\u6570\u636e\u5305\uff0c\u5e76\u4e14\u5df2\u7ecf\u4e3a\u8fd9\u4e2a\u8fde\u63a5\u751f\u6210\u4e86\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u5217\u53f7\u3002<\/p>\n

          ACK = 1 \u8fd9\u4e2a\u6807\u5fd7\u4f4d\u53ea\u662f\u8868\u793a\u6570\u636e\u5305\u4e2d\u5305\u542b\u4e86\u4e00\u4e2a\u786e\u8ba4\u53f7\uff0c\u4f46\u5b83\u672c\u8eab\u5e76\u4e0d\u80fd\u786e\u8ba4\u670d\u52a1\u5668\u662f\u5426\u6b63\u786e\u63a5\u6536\u5230\u4e86\u5ba2\u6237\u7aef\u7684\u8bf7\u6c42\u3002\u901a\u8fc7\u68c0\u67e5\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u662f\u5426\u4e3aX+1\uff0c\u5ba2\u6237\u7aef\u53ef\u4ee5\u786e\u4fdd\u670d\u52a1\u5668\u5df2\u7ecf\u6210\u529f\u63a5\u6536\u5230\u4e86\u8fde\u63a5\u8bf7\u6c42\u3002\u8fd9\u6837\u7684\u8bbe\u8ba1\u6709\u52a9\u4e8e\u63d0\u9ad8TCP\u534f\u8bae\u7684\u53ef\u9760\u6027\u3002<\/p>\n

          \"image-20230315153842398\" <\/p>\n

          \u901a\u4fd7\u7406\u89e3<\/h3>\n

          \u4e09\u6b21\u63e1\u624b\u7684\u8fc7\u7a0b\u53ef\u4ee5\u7c7b\u6bd4\u4e3a\u4e24\u4e2a\u4eba\u63e1\u624b\u3002\u5047\u8bbeA\u548cB\u4e24\u4e2a\u4eba\u89c1\u9762\uff0c\u8981\u8fdb\u884c\u63e1\u624b\u8868\u793a\u5efa\u7acb\u8054\u7cfb\u3002\u63e1\u624b\u7684\u8fc7\u7a0b\u5982\u4e0b\uff1a<\/p>\n

            \n
          1. A\u5411B\u4f38\u51fa\u624b\u5e76\u8bf4\uff1a\u201c\u4f60\u597d\uff0c\u6211\u662fA\uff0c\u4f60\u613f\u610f\u548c\u6211\u63e1\u624b\u5417\uff1f\u201d<\/li>\n
          2. B\u770b\u5230A\u7684\u624b\uff0c\u60f3\u8981\u4e0eA\u63e1\u624b\uff0c\u4e8e\u662f\u56de\u7b54\uff1a\u201c\u4f60\u597d\uff0c\u6211\u662fB\uff0c\u6211\u613f\u610f\u548c\u4f60\u63e1\u624b\u3002\u201d\u540c\u65f6\uff0cB\u4e5f\u5411A\u4f38\u51fa\u624b\u3002<\/li>\n
          3. A\u770b\u5230B\u7684\u624b\uff0c\u786e\u8ba4\u5bf9\u65b9\u613f\u610f\u4e0e\u81ea\u5df1\u63e1\u624b\uff0c\u4e8e\u662f\u56de\u7b54\uff1a\u201c\u597d\u7684\uff0c\u6211\u4eec\u63e1\u624b\u5427\u3002\u201d\u7136\u540e\u4e0eB\u63e1\u624b\u3002<\/li>\n<\/ol>\n

            \u7c7b\u6bd4\u5230TCP\u4e09\u6b21\u63e1\u624b\u7684\u8fc7\u7a0b\u4e2d\uff0cA\u548cB\u5206\u522b\u8868\u793a\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\uff0c\u63e1\u624b\u7684\u8fc7\u7a0b\u4e2d\u53d1\u9001\u65b9\u53d1\u9001SYN\u62a5\u6587\u6bb5\u8868\u793a\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\uff0c\u63a5\u6536\u65b9\u53d1\u9001SYN+ACK\u62a5\u6587\u6bb5\u8868\u793a\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u6700\u540e\u53d1\u9001\u65b9\u518d\u53d1\u9001ACK\u62a5\u6587\u6bb5\u8868\u793a\u786e\u8ba4\u8fde\u63a5\u5efa\u7acb\u6210\u529f\u3002<\/p>\n

            TCP\u56db\u6b21\u6325\u624b<\/h2>\n
            \n

            TCP\u56db\u6b21\u6325\u624b\u662f\u7ec8\u6b62TCP\u8fde\u63a5\u7684\u8fc7\u7a0b\uff0c\u901a\u8fc7\u56db\u6b21\u6325\u624b\uff0c\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\u53ef\u4ee5\u5b8c\u6210\u6570\u636e\u4f20\u8f93\uff0c\u91ca\u653e\u8fde\u63a5\u8d44\u6e90\u3002<\/p>\n<\/blockquote>\n

              \n
            1. \u7b2c\u4e00\u6b21\u6325\u624b\uff08FIN\uff09\uff1a<\/li>\n<\/ol>\n

              \u5ba2\u6237\u7aef\u51b3\u5b9a\u4e0d\u518d\u53d1\u9001\u6570\u636e\u65f6\uff0c\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001\u4e00\u4e2aFIN\uff08\u7ed3\u675f\uff09\u62a5\u6587\u6bb5\uff08FIN=Finish\uff09\uff0c\u8868\u793a\u5ba2\u6237\u7aef\u4e0d\u518d\u53d1\u9001\u6570\u636e\uff0c\u5e76\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165FIN_WAIT_1\u72b6\u6001\u3002<\/p>\n

                \n
              1. \u7b2c\u4e8c\u6b21\u6325\u624b\uff08ACK\uff09\uff1a<\/li>\n<\/ol>\n

                \u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684FIN\u62a5\u6587\u6bb5\u540e\uff0c\u4f1a\u5411\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aACK\uff08\u786e\u8ba4\uff09\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u670d\u52a1\u5668\u5df2\u7ecf\u6210\u529f\u63a5\u6536\u5ba2\u6237\u7aef\u7684FIN\u62a5\u6587\u6bb5\uff0c\u5e76\u5411\u5ba2\u6237\u7aef\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u3002\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165FIN_WAIT_2\u72b6\u6001\uff0c\u7b49\u5f85\u670d\u52a1\u5668\u5173\u95ed\u8fde\u63a5\u3002<\/p>\n

                  \n
                1. \u7b2c\u4e09\u6b21\u6325\u624b\uff08FIN\uff09\uff1a<\/li>\n<\/ol>\n

                  \u5f53\u670d\u52a1\u5668\u5b8c\u6210\u6570\u636e\u53d1\u9001\u5e76\u51c6\u5907\u597d\u5173\u95ed\u8fde\u63a5\u65f6\uff0c\u5b83\u4f1a\u5411\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aFIN\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u670d\u52a1\u5668\u4e5f\u4e0d\u518d\u53d1\u9001\u6570\u636e\uff0c\u5e76\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\u6b64\u65f6\uff0c\u670d\u52a1\u5668\u8fdb\u5165LAST_ACK\u72b6\u6001\uff0c\u7b49\u5f85\u5ba2\u6237\u7aef\u7684\u6700\u540e\u786e\u8ba4\u3002<\/p>\n

                    \n
                  1. \u7b2c\u56db\u6b21\u6325\u624b\uff08ACK\uff09\uff1a<\/li>\n<\/ol>\n

                    \u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u53d1\u9001\u7684FIN\u62a5\u6587\u6bb5\u540e\uff0c\u5411\u670d\u52a1\u5668\u53d1\u9001\u4e00\u4e2aACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u5ba2\u6237\u7aef\u5df2\u7ecf\u6210\u529f\u6536\u5230\u4e86\u670d\u52a1\u5668\u7684FIN\u62a5\u6587\u6bb5\uff0c\u5e76\u5411\u670d\u52a1\u5668\u53d1\u9001\u786e\u8ba4\u4fe1\u606f\u3002\u6b64\u65f6\uff0c\u670d\u52a1\u5668\u5173\u95ed\u8fde\u63a5\uff0cTCP\u8fde\u63a5\u5df2\u7ecf\u5b8c\u5168\u7ec8\u6b62\uff0c\u8fde\u63a5\u8d44\u6e90\u88ab\u91ca\u653e\u3002\u5ba2\u6237\u7aef\u7b49\u5f85\u4e00\u6bb5\u65f6\u95f4\uff08\u901a\u5e38\u662f2\u500d\u7684\u6700\u5927\u5206\u6bb5\u751f\u5b58\u65f6\u95f4\uff0cMSL\uff09\uff0c\u7136\u540e\u5173\u95ed\u8fde\u63a5\u91ca\u653e\u76f8\u5173\u8d44\u6e90\u3002\u8fd9\u4e2a\u7b49\u5f85\u65f6\u95f4\u786e\u4fdd\u4e86\u670d\u52a1\u5668\u80fd\u591f\u6536\u5230\u5ba2\u6237\u7aef\u7684\u6700\u540e\u4e00\u4e2aACK\u62a5\u6587\u3002<\/p>\n

                    \u5728TCP\u56db\u6b21\u6325\u624b\u7684\u8fc7\u7a0b\u4e2d\uff0c\u6709\u4e00\u4e2aTIME_WAIT\u72b6\u6001\uff0c\u662f\u4e3a\u4e86\u9632\u6b62\u51fa\u73b0\u201c\u534a\u5f00\u8fde\u63a5\u201d\u7684\u60c5\u51b5\uff0c\u4fdd\u8bc1\u8fde\u63a5\u7684\u6b63\u786e\u5173\u95ed\u3002\u5728\u5ba2\u6237\u7aef\u53d1\u9001\u6700\u540e\u4e00\u4e2aACK\u62a5\u6587\u6bb5\u4e4b\u540e\uff0c\u4f1a\u8fdb\u5165TIME_WAIT\u72b6\u6001\uff0c\u7b49\u5f852\u500dMSL\uff08Maximum Segment Lifetime\uff0c\u6700\u5927\u62a5\u6587\u6bb5\u751f\u5b58\u65f6\u95f4\uff09\u65f6\u95f4\uff0c\u786e\u4fdd\u6240\u6709\u7684\u6570\u636e\u90fd\u5df2\u7ecf\u4f20\u8f93\u5b8c\u6210\u3002\u5982\u679c\u5728TIME_WAIT\u72b6\u6001\u671f\uff0c\u63a5\u6536\u5230\u4e86\u670d\u52a1\u5668\u53d1\u9001\u7684FIN\u62a5\u6587\u6bb5\uff0c\u8bf4\u660e\u670d\u52a1\u5668\u5e76\u6ca1\u6709\u63a5\u6536\u5230ACK\u62a5\u6587\u6bb5\uff0c\u6b64\u65f6\u5ba2\u6237\u7aef\u9700\u8981\u91cd\u65b0\u53d1\u9001ACK\u62a5\u6587\u6bb5\u3002\u5982\u679c\u8d85\u8fc72\u500dMSL\u65f6\u95f4\u540e\u8fd8\u6ca1\u6709\u6536\u5230\u670d\u52a1\u5668\u53d1\u9001\u7684FIN\u62a5\u6587\u6bb5\uff0c\u5ba2\u6237\u7aef\u5c31\u53ef\u4ee5\u7ed3\u675fTIME_WAIT\u72b6\u6001\uff0c\u91ca\u653e\u8fde\u63a5\u8d44\u6e90\u3002<\/p>\n

                    \u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u5728TCP\u8fde\u63a5\u7684\u5efa\u7acb\u548c\u7ec8\u6b62\u8fc7\u7a0b\u4e2d\uff0c\u5982\u679c\u5176\u4e2d\u4e00\u65b9\u6ca1\u6709\u6309\u7167\u89c4\u5b9a\u7684\u6b65\u9aa4\u8fdb\u884c\u64cd\u4f5c\uff0c\u6216\u8005\u51fa\u73b0\u7f51\u7edc\u6545\u969c\u7b49\u60c5\u51b5\uff0c\u5c31\u4f1a\u5bfc\u81f4TCP\u8fde\u63a5\u65e0\u6cd5\u6b63\u5e38\u5efa\u7acb\u6216\u8005\u7ec8\u6b62\u3002\u6bd4\u5982\uff0c\u5982\u679c\u53ea\u8fdb\u884c\u4e86\u4e24\u6b21\u63e1\u624b\uff0c\u5c31\u53ef\u4ee5\u4f2a\u9020\u4e00\u4e2aTCP\u8fde\u63a5\uff0c\u8fd9\u5c31\u662fTCP\u7684SYN\u653b\u51fb\u3002\u56e0\u6b64\uff0cTCP\u534f\u8bae\u7684\u5b89\u5168\u6027\u4e5f\u6210\u4e3a\u7f51\u7edc\u5b89\u5168\u7684\u91cd\u8981\u95ee\u9898\u4e4b\u4e00\u3002<\/p>\n

                    \"image-20230315170411941\" <\/p>\n

                    \u901a\u4fd7\u7406\u89e3<\/h3>\n

                    \u56db\u6b21\u6325\u624b\u7684\u8fc7\u7a0b\u4e5f\u53ef\u4ee5\u7c7b\u6bd4\u4e3a\u4e24\u4e2a\u4eba\u6325\u624b\u3002\u5047\u8bbeA\u548cB\u4e24\u4e2a\u4eba\u8981\u7ed3\u675f\u4f1a\u9762\uff0c\u8fdb\u884c\u6325\u624b\u7684\u8fc7\u7a0b\u5982\u4e0b\uff1a<\/p>\n

                      \n
                    1. A\u5bf9B\u8bf4\uff1a\u201c\u5f88\u9ad8\u5174\u80fd\u4e0e\u4f60\u89c1\u9762\uff0c\u6211\u4eec\u8be5\u7ed3\u675f\u4e86\u3002\u201d\u7136\u540eA\u79bb\u5f00\u3002<\/li>\n
                    2. B\u56de\u7b54\uff1a\u201c\u597d\u7684\uff0c\u6211\u4eec\u4e0b\u6b21\u518d\u89c1\u3002\u201d<\/li>\n
                    3. \u7136\u540e\uff0cB\u4e5f\u544a\u8bc9A\uff1a\u201c\u8bf7\u786e\u8ba4\u6536\u5230\u6211\u7684\u6d88\u606f\u3002\u201d<\/li>\n
                    4. A\u56de\u7b54\uff1a\u201c\u597d\u7684\uff0c\u6211\u5df2\u7ecf\u6536\u5230\u4e86\uff0c\u518d\u89c1\u3002\u201d\u6700\u540eA\u4e5f\u79bb\u5f00\u3002<\/li>\n<\/ol>\n

                      \u7c7b\u6bd4\u5230TCP\u56db\u6b21\u6325\u624b\u7684\u8fc7\u7a0b\u4e2d\uff0cA\u548cB\u5206\u522b\u8868\u793a\u53d1\u9001\u65b9\u548c\u63a5\u6536\u65b9\uff0c\u6325\u624b\u7684\u8fc7\u7a0b\u4e2d\u53d1\u9001\u65b9\u53d1\u9001FIN\u62a5\u6587\u6bb5\u8868\u793a\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\uff0c\u63a5\u6536\u65b9\u53d1\u9001ACK\u62a5\u6587\u6bb5\u8868\u793a\u5df2\u7ecf\u6536\u5230\u8bf7\u6c42\uff0c\u7136\u540e\u63a5\u6536\u65b9\u4e5f\u53d1\u9001FIN\u62a5\u6587\u6bb5\u8868\u793a\u4e5f\u8981\u5173\u95ed\u8fde\u63a5\uff0c\u6700\u540e\u53d1\u9001\u65b9\u518d\u53d1\u9001ACK\u62a5\u6587\u6bb5\u8868\u793a\u786e\u8ba4\u8fde\u63a5\u5173\u95ed\u6210\u529f\u3002<\/p>\n

                      \u516d\u5927\u6807\u5fd7\u4f4d<\/h2>\n
                      \n

                      TCP\u4e2d\u6709\u516d\u5927\u6807\u5fd7\u4f4d\uff1aSYN\u3001ACK\u3001FIN\uff0c\u8fd9\u4e09\u4e2a\u6700\u4e3a\u91cd\u8981\uff0c\u8fd8\u6709URG\u3001PSH\u3001RSE\uff0c\u8fd9\u4e9b\u90fd\u662fTCP\u534f\u8bae\u4e2d\u7684\u63a7\u5236\u6807\u5fd7\uff08Control flag\uff09\uff0c\u7528\u6765\u63a7\u5236TCP\u62a5\u6587\u6bb5\u7684\u884c\u4e3a\u3002<\/p>\n<\/blockquote>\n

                      SYN\u8868\u793a\u201c\u540c\u6b65\u201d\uff0c\u5b83\u662f\u4e00\u4e2a\u8bf7\u6c42\u6807\u5fd7\u4f4d\uff0c\u7528\u4e8e\u544a\u8bc9\u63a5\u6536\u65b9\uff0c\u53d1\u9001\u65b9\u6253\u7b97\u5efa\u7acb\u4e00\u4e2a\u65b0\u7684TCP\u8fde\u63a5\u3002SYN\u62a5\u6587\u6bb5\u4e2d\uff0cSYN\u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a1\uff0c\u5176\u4f59\u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a0\u3002<\/p>\n

                      ACK\u8868\u793a\u201c\u786e\u8ba4\u201d\uff0c\u5b83\u662f\u4e00\u4e2a\u54cd\u5e94\u6807\u5fd7\u4f4d\uff0c\u7528\u4e8e\u544a\u8bc9\u53d1\u9001\u65b9\uff0c\u63a5\u6536\u65b9\u5df2\u7ecf\u6536\u5230\u4e86\u53d1\u9001\u65b9\u53d1\u9001\u7684\u62a5\u6587\u6bb5\u3002ACK\u62a5\u6587\u6bb5\u4e2d\uff0cACK\u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a1\uff0c\u5176\u4f59\u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a0\u3002<\/p>\n

                      \u5728TCP\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\uff0c\u5f53\u53d1\u9001\u65b9\u5411\u63a5\u6536\u65b9\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\u65f6\uff0c\u63a5\u6536\u65b9\u4f1a\u56de\u590d\u4e00\u4e2aSYN-ACK\u62a5\u6587\u6bb5\uff0c\u5176\u4e2dSYN\u548cACK\u6807\u5fd7\u4f4d\u90fd\u88ab\u8bbe\u7f6e\u4e3a1\u3002\u8fd9\u610f\u5473\u7740\u63a5\u6536\u65b9\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u5e76\u4e14\u5411\u53d1\u9001\u65b9\u53d1\u9001\u786e\u8ba4\u62a5\u6587\u6bb5\u3002\u63a5\u6536\u65b9\u7684SYN\u62a5\u6587\u6bb5\u4e2d\u7684SYN\u6807\u5fd7\u4f4d\u544a\u8bc9\u53d1\u9001\u65b9\uff0c\u63a5\u6536\u65b9\u5df2\u7ecf\u6536\u5230\u4e86\u53d1\u9001\u65b9\u7684SYN\u62a5\u6587\u6bb5\uff0c\u800cSYN-ACK\u62a5\u6587\u6bb5\u4e2d\u7684ACK\u6807\u5fd7\u4f4d\u544a\u8bc9\u53d1\u9001\u65b9\uff0c\u63a5\u6536\u65b9\u5df2\u7ecf\u786e\u8ba4\u4e86\u5efa\u7acb\u8fde\u63a5\u7684\u8bf7\u6c42\u3002<\/p>\n

                      \u5f53\u53d1\u9001\u65b9\u6536\u5230\u63a5\u6536\u65b9\u7684SYN-ACK\u62a5\u6587\u6bb5\u540e\uff0c\u4f1a\u5411\u63a5\u6536\u65b9\u53d1\u9001\u4e00\u4e2aACK\u62a5\u6587\u6bb5\uff0c\u5176\u4e2dACK\u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a1\u3002\u8fd9\u610f\u5473\u7740\u53d1\u9001\u65b9\u5df2\u7ecf\u6536\u5230\u4e86\u63a5\u6536\u65b9\u7684\u786e\u8ba4\u62a5\u6587\u6bb5\uff0c\u8fde\u63a5\u5df2\u7ecf\u5efa\u7acb\u6210\u529f\u3002<\/p>\n

                      \u56e0\u6b64\uff0cSYN\u548cACK\u6807\u5fd7\u4f4d\u5728TCP\u534f\u8bae\u4e2d\u662f\u975e\u5e38\u91cd\u8981\u7684\u6807\u5fd7\u4f4d\uff0c\u5b83\u4eec\u7528\u4e8e\u786e\u4fddTCP\u8fde\u63a5\u7684\u53ef\u9760\u6027\u548c\u6b63\u786e\u6027\u3002<\/p>\n

                        \n
                      1. SYN\uff08\u540c\u6b65\u5e8f\u5217\u7f16\u53f7 \uff0cSynchronize Sequence Numbers\uff09\u6807\u5fd7\u4f4d\uff1a\u7528\u4e8e\u5efa\u7acb\u8fde\u63a5\u65f6\u7684\u63e1\u624b\u8fc7\u7a0b\u3002\u53d1\u9001\u7aef\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\uff0c\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\uff0c\u540c\u65f6SYN\u6807\u5fd7\u4f4d\u4e3a1\u3002\u63a5\u6536\u7aef\u6536\u5230SYN\u62a5\u6587\u6bb5\u540e\uff0c\u56de\u590d\u4e00\u4e2aSYN+ACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0cSYN\u548cACK\u6807\u5fd7\u4f4d\u90fd\u4e3a1\u3002\u8fd9\u662fTCP\u4e09\u6b21\u63e1\u624b\u7684\u7b2c\u4e00\u6b65\u548c\u7b2c\u4e8c\u6b65\u3002<\/li>\n
                      2. ACK\uff08Acknowledgment\uff09\u6807\u5fd7\u4f4d\uff1a\u7528\u4e8e\u786e\u8ba4\u63a5\u6536\u65b9\u662f\u5426\u6b63\u786e\u63a5\u6536\u5230\u4e86\u62a5\u6587\u6bb5\u3002\u5728\u6b63\u5e38\u7684\u6570\u636e\u4f20\u8f93\u8fc7\u7a0b\u4e2d\uff0c\u53d1\u9001\u7aef\u53d1\u9001\u4e00\u4e2a\u5305\u542b\u6570\u636e\u7684TCP\u62a5\u6587\u6bb5\uff0cACK\u6807\u5fd7\u4f4d\u4e3a1\uff0c\u8868\u793a\u63a5\u6536\u65b9\u9700\u8981\u786e\u8ba4\u8fd9\u4e2a\u62a5\u6587\u6bb5\u5df2\u7ecf\u88ab\u6b63\u786e\u63a5\u6536\u3002\u63a5\u6536\u65b9\u5728\u6b63\u786e\u63a5\u6536\u5230\u62a5\u6587\u6bb5\u540e\uff0c\u56de\u590d\u4e00\u4e2aACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u5df2\u7ecf\u6b63\u786e\u63a5\u6536\u5230\u3002<\/li>\n
                      3. FIN\uff08Finish\uff09\u6807\u5fd7\u4f4d\uff1a\u7528\u4e8e\u5173\u95edTCP\u8fde\u63a5\u65f6\u7684\u56db\u6b21\u6325\u624b\u8fc7\u7a0b\u3002\u53d1\u9001\u65b9\u5411\u63a5\u6536\u65b9\u53d1\u9001\u4e00\u4e2aFIN\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u4e0d\u518d\u53d1\u9001\u6570\u636e\uff0c\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\u63a5\u6536\u65b9\u6536\u5230FIN\u62a5\u6587\u6bb5\u540e\uff0c\u56de\u590d\u4e00\u4e2aACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u5df2\u7ecf\u6536\u5230\u8bf7\u6c42\uff0c\u4f46\u4ecd\u7136\u53ef\u4ee5\u53d1\u9001\u6570\u636e\u3002\u5f53\u63a5\u6536\u65b9\u4e5f\u51c6\u5907\u597d\u5173\u95ed\u8fde\u63a5\u65f6\uff0c\u4f1a\u5411\u53d1\u9001\u65b9\u53d1\u9001\u4e00\u4e2aFIN\u62a5\u6587\u6bb5\uff0c\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\u53d1\u9001\u65b9\u6536\u5230FIN\u62a5\u6587\u6bb5\u540e\uff0c\u56de\u590d\u4e00\u4e2aACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u786e\u8ba4\u5173\u95ed\u8fde\u63a5\u3002\u8fd9\u662fTCP\u56db\u6b21\u6325\u624b\u7684\u6700\u540e\u4e00\u6b65\u3002<\/li>\n
                      4. URG\uff08Urgent\uff09\u6807\u5fd7\u4f4d\uff1a\u5f53\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u4e3a1\u65f6\uff0c\u8868\u793a\u7d27\u6025\u6307\u9488\uff08urgent pointer\uff09\u5b57\u6bb5\u6709\u6548\uff0c\u7d27\u6025\u6307\u9488\u7528\u4e8e\u6307\u793a\u7d27\u6025\u6570\u636e\u7684\u8fb9\u754c\uff0c\u901a\u5e38\u7528\u4e8e\u5b9e\u65f6\u901a\u4fe1\u7b49\u573a\u666f\u3002<\/li>\n
                      5. PSH\uff08Push\uff09\u6807\u5fd7\u4f4d\uff1a\u5f53\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u4e3a1\u65f6\uff0c\u8868\u793a\u63a5\u6536\u65b9\u5e94\u8be5\u5c3d\u5feb\u5c06\u6570\u636e\u4ea4\u7ed9\u5e94\u7528\u7a0b\u5e8f\uff0c\u800c\u4e0d\u662f\u7b49\u5230\u7f13\u51b2\u533a\u6ee1\u4e86\u518d\u4ea4\u7ed9\u5e94\u7528\u7a0b\u5e8f\u3002<\/li>\n
                      6. RST\uff08Reset\uff09\u6807\u5fd7\u4f4d\uff1a\u5f53\u8fd9\u4e2a\u6807\u5fd7\u4f4d\u4e3a1\u65f6\uff0c\u8868\u793a\u91cd\u7f6eTCP\u8fde\u63a5\uff0c\u901a\u5e38\u7528\u4e8e\u4e2d\u65ad\u8fde\u63a5\u6216\u8005\u53d1\u751f\u9519\u8bef\u65f6\u3002<\/li>\n<\/ol>\n
                        1.SYN\uff08Synchronize\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u8fde\u63a5\u5efa\u7acb\u8fc7\u7a0b\u4e2d\u4f7f\u7528\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002TCP \u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u534f\u8bae\u3002\u5728 TCP \u4f20\u8f93\u4e2d\uff0c\u5efa\u7acb\u8fde\u63a5\u524d\u9700\u8981\u8fdb\u884c\u4e00\u4e2a\u79f0\u4e3a "\u4e09\u6b21\u63e1\u624b"\uff08Three-way Handshake\uff09\u7684\u8fc7\u7a0b\u3002SYN \u662f\u8fd9\u4e2a\u8fc7\u7a0b\u7684\u5173\u952e\u90e8\u5206\u3002\n\n\u4e09\u6b21\u63e1\u624b\u7684\u6b65\u9aa4\u5982\u4e0b\uff1a\n\n\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001\u4e00\u4e2a TCP \u6570\u636e\u5305\uff0c\u5176\u4e2d SYN \u6807\u5fd7\u4f4d\u8bbe\u7f6e\u4e3a 1\u3002\u8fd9\u8868\u793a\u5ba2\u6237\u7aef\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u3002\u540c\u65f6\uff0c\u5ba2\u6237\u7aef\u4f1a\u8bbe\u7f6e\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff08ISN\uff09\u3002\n\u670d\u52a1\u5668\u6536\u5230 SYN \u6570\u636e\u5305\u540e\uff0c\u5982\u679c\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u4f1a\u56de\u590d\u4e00\u4e2a TCP \u6570\u636e\u5305\uff0c\u5176\u4e2d SYN \u6807\u5fd7\u4f4d\u548c ACK\uff08Acknowledge\uff0c\u786e\u8ba4\uff09\u6807\u5fd7\u4f4d\u90fd\u8bbe\u7f6e\u4e3a 1\u3002\u670d\u52a1\u5668\u4e5f\u4f1a\u8bbe\u7f6e\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u5217\u53f7\u3002\n\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684\u56de\u590d\u540e\uff0c\u4f1a\u53d1\u9001\u4e00\u4e2a TCP \u6570\u636e\u5305\uff0c\u5176\u4e2d ACK \u6807\u5fd7\u4f4d\u8bbe\u7f6e\u4e3a 1\uff0c\u4ee5\u786e\u8ba4\u6536\u5230\u670d\u52a1\u5668\u7684 SYN-ACK \u6570\u636e\u5305\u3002\u6b64\u65f6\uff0cTCP \u8fde\u63a5\u5efa\u7acb\u5b8c\u6210\uff0c\u53ef\u4ee5\u5f00\u59cb\u6570\u636e\u4f20\u8f93\u3002\n\u5728 nmap \u4e2d\uff0cSYN \u626b\u63cf\uff08-sS\uff09\u662f\u4e00\u79cd\u8f83\u5feb\u4e14\u4e0d\u6613\u88ab\u68c0\u6d4b\u5230\u7684\u7aef\u53e3\u626b\u63cf\u65b9\u6cd5\u3002SYN \u626b\u63cf\u7684\u539f\u7406\u662f\u53d1\u9001\u4e00\u4e2a SYN \u6570\u636e\u5305\u5230\u76ee\u6807\u4e3b\u673a\u7684\u6307\u5b9a\u7aef\u53e3\uff0c\u7136\u540e\u6839\u636e\u4e3b\u673a\u7684\u54cd\u5e94\u5224\u65ad\u8be5\u7aef\u53e3\u7684\u72b6\u6001\u3002\u5982\u679c\u6536\u5230\u4e00\u4e2a SYN-ACK \u6570\u636e\u5305\uff0c\u8bf4\u660e\u7aef\u53e3\u5904\u4e8e\u5f00\u653e\u72b6\u6001\uff1b\u5982\u679c\u6536\u5230\u4e00\u4e2a RST\uff08Reset\uff0c\u91cd\u7f6e\uff09\u6570\u636e\u5305\uff0c\u8bf4\u660e\u7aef\u53e3\u5904\u4e8e\u5173\u95ed\u72b6\u6001\u3002SYN \u626b\u63cf\u4e0d\u4f1a\u5b8c\u6210\u5b8c\u6574\u7684 TCP \u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\uff0c\u56e0\u6b64\u5b83\u88ab\u79f0\u4e3a "\u534a\u5f00\u653e"\uff08Half-open\uff09\u626b\u63cf\u3002<\/code><\/pre>\n
                        2.RST\uff08Reset\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002RST \u7528\u4e8e\u8868\u793a\u8fde\u63a5\u51fa\u73b0\u9519\u8bef\u6216\u5f02\u5e38\uff0c\u9700\u8981\u7acb\u5373\u7ec8\u6b62\uff08\u91cd\u7f6e\uff09\u5f53\u524d\u8fde\u63a5\u3002\u5728 TCP \u6570\u636e\u5305\u4e2d\uff0c\u5982\u679c RST \u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a 1\uff0c\u8bf4\u660e\u63a5\u6536\u65b9\u62d2\u7edd\u4e86\u8be5\u8fde\u63a5\u6216\u6307\u793a\u53d1\u9001\u65b9\u7ec8\u6b62\u8fde\u63a5\u3002\n\nRST \u5728\u4ee5\u4e0b\u573a\u666f\u4e2d\u53ef\u80fd\u4f1a\u88ab\u4f7f\u7528\uff1a\n\n\u5f53\u4e00\u4e2a TCP \u8fde\u63a5\u7684\u4e00\u7aef\u63a5\u6536\u5230\u4e00\u4e2a\u4e0d\u7b26\u5408\u671f\u671b\u7684\u6570\u636e\u5305\u65f6\uff0c\u5982\u5e8f\u5217\u53f7\u4e0d\u5339\u914d\u7684\u6570\u636e\u5305\uff0c\u5b83\u53ef\u80fd\u4f1a\u56de\u590d\u4e00\u4e2a RST \u6570\u636e\u5305\uff0c\u4ee5\u901a\u77e5\u5bf9\u7aef\u5173\u95ed\u8fde\u63a5\u3002\n\u5982\u679c\u670d\u52a1\u5668\u63a5\u6536\u5230\u4e00\u4e2a SYN \u6570\u636e\u5305\uff0c\u4f46\u76ee\u6807\u7aef\u53e3\u5904\u4e8e\u5173\u95ed\u72b6\u6001\uff0c\u670d\u52a1\u5668\u53ef\u80fd\u4f1a\u56de\u590d\u4e00\u4e2a RST \u6570\u636e\u5305\uff0c\u4ee5\u544a\u77e5\u5ba2\u6237\u7aef\u7aef\u53e3\u4e0d\u53ef\u7528\u3002\n\u5728 nmap \u7aef\u53e3\u626b\u63cf\u4e2d\uff0cRST \u6570\u636e\u5305\u7684\u54cd\u5e94\u901a\u5e38\u8868\u793a\u76ee\u6807\u7aef\u53e3\u5904\u4e8e\u5173\u95ed\u72b6\u6001\u3002\u4f8b\u5982\uff0c\u5728 SYN \u626b\u63cf\uff08-sS\uff09\u4e2d\uff0cnmap \u4f1a\u53d1\u9001\u4e00\u4e2a SYN \u6570\u636e\u5305\u5230\u76ee\u6807\u4e3b\u673a\u7684\u6307\u5b9a\u7aef\u53e3\u3002\u5982\u679c\u6536\u5230\u4e00\u4e2a RST \u6570\u636e\u5305\uff0c\u8bf4\u660e\u7aef\u53e3\u5904\u4e8e\u5173\u95ed\u72b6\u6001\u3002\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cnmap \u4e0d\u4f1a\u5b8c\u6210 TCP \u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\uff0c\u800c\u662f\u6839\u636e\u6536\u5230\u7684 RST \u6570\u636e\u5305\u5224\u65ad\u7aef\u53e3\u72b6\u6001\u3002<\/code><\/pre>\n
                        3.ACK\uff08Acknowledge\uff0c\u786e\u8ba4\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002ACK \u7528\u4e8e\u8868\u793a\u63a5\u6536\u65b9\u5df2\u6210\u529f\u6536\u5230\u53d1\u9001\u65b9\u4f20\u8f93\u7684\u6570\u636e\uff0c\u4ee5\u4fdd\u8bc1\u6570\u636e\u4f20\u8f93\u7684\u53ef\u9760\u6027\u3002\u5728 TCP \u6570\u636e\u5305\u4e2d\uff0c\u5982\u679c ACK \u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a 1\uff0c\u8bf4\u660e\u63a5\u6536\u65b9\u786e\u8ba4\u6536\u5230\u4e86\u53d1\u9001\u65b9\u7684\u6570\u636e\u5305\u3002\n\nTCP \u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u534f\u8bae\u3002\u5728 TCP \u4f20\u8f93\u4e2d\uff0c\u53d1\u9001\u65b9\u5728\u4f20\u8f93\u6570\u636e\u540e\u9700\u8981\u7b49\u5f85\u63a5\u6536\u65b9\u7684\u786e\u8ba4\uff08ACK \u6570\u636e\u5305\uff09\uff0c\u4ee5\u786e\u4fdd\u6570\u636e\u5df2\u6210\u529f\u4f20\u8f93\u3002\u5982\u679c\u53d1\u9001\u65b9\u5728\u4e00\u5b9a\u65f6\u95f4\u5185\u672a\u6536\u5230 ACK \u6570\u636e\u5305\uff0c\u5b83\u4f1a\u91cd\u65b0\u53d1\u9001\u6570\u636e\u5305\uff0c\u76f4\u5230\u6536\u5230\u786e\u8ba4\u6216\u8d85\u8fc7\u91cd\u8bd5\u6b21\u6570\u3002\n\nACK \u5728 TCP \u4f20\u8f93\u4e2d\u7684\u4e3b\u8981\u7528\u9014\u5982\u4e0b\uff1a\n\n\u5728 TCP \u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\uff0cACK \u6570\u636e\u5305\u7528\u4e8e\u786e\u8ba4\u6536\u5230 SYN \u6570\u636e\u5305\uff0c\u4ece\u800c\u5efa\u7acb\u8fde\u63a5\u3002\n\u5728 TCP \u6570\u636e\u4f20\u8f93\u8fc7\u7a0b\u4e2d\uff0cACK \u6570\u636e\u5305\u7528\u4e8e\u786e\u8ba4\u6536\u5230\u6570\u636e\u5305\uff0c\u4fdd\u8bc1\u6570\u636e\u7684\u53ef\u9760\u4f20\u8f93\u3002\n\u5728 TCP \u56db\u6b21\u6325\u624b\u8fc7\u7a0b\u4e2d\uff0cACK \u6570\u636e\u5305\u7528\u4e8e\u786e\u8ba4\u6536\u5230 FIN\uff08Finish\uff0c\u5b8c\u6210\uff09\u6570\u636e\u5305\uff0c\u4ee5\u7ec8\u6b62\u8fde\u63a5\u3002\n\u5728 nmap \u7684 SYN \u626b\u63cf\uff08-sS\uff09\u4e2d\uff0cACK \u6807\u5fd7\u4f4d\u4e5f\u6709\u91cd\u8981\u4f5c\u7528\u3002\u5f53\u76ee\u6807\u4e3b\u673a\u7684\u7aef\u53e3\u5904\u4e8e\u5f00\u653e\u72b6\u6001\u65f6\uff0c\u5b83\u4f1a\u56de\u590d\u4e00\u4e2a SYN-ACK \u6570\u636e\u5305\uff08SYN \u548c ACK \u6807\u5fd7\u4f4d\u90fd\u8bbe\u7f6e\u4e3a 1\uff09\u4ee5\u786e\u8ba4\u6536\u5230 SYN \u6570\u636e\u5305\u3002nmap \u4f1a\u6839\u636e\u6536\u5230\u7684 SYN-ACK \u6570\u636e\u5305\u5224\u65ad\u7aef\u53e3\u72b6\u6001\uff0c\u5e76\u5728\u626b\u63cf\u8fc7\u7a0b\u4e2d\u53d1\u9001 RST \u6570\u636e\u5305\u4ee5\u4e2d\u6b62\u8fde\u63a5\uff0c\u4ece\u800c\u907f\u514d\u5b8c\u6210 TCP \u4e09\u6b21\u63e1\u624b\u3002\u8fd9\u4f7f\u5f97 SYN \u626b\u63cf\u6210\u4e3a\u4e00\u79cd\u8f83\u5feb\u4e14\u4e0d\u6613\u88ab\u68c0\u6d4b\u5230\u7684\u7aef\u53e3\u626b\u63cf\u65b9\u6cd5\u3002<\/code><\/pre>\n
                        4.FIN\uff08Finish\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002FIN \u7528\u4e8e\u8868\u793a\u4e00\u65b9\u5df2\u5b8c\u6210\u6570\u636e\u4f20\u8f93\uff0c\u5e0c\u671b\u5173\u95ed\u8fde\u63a5\u3002\u5728 TCP \u6570\u636e\u5305\u4e2d\uff0c\u5982\u679c FIN \u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a 1\uff0c\u8bf4\u660e\u53d1\u9001\u65b9\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\n\nTCP \u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u534f\u8bae\u3002\u5f53 TCP \u8fde\u63a5\u4e2d\u7684\u4e00\u65b9\u5b8c\u6210\u6570\u636e\u4f20\u8f93\u5e76\u51c6\u5907\u5173\u95ed\u8fde\u63a5\u65f6\uff0c\u5b83\u4f1a\u53d1\u9001\u4e00\u4e2a FIN \u6570\u636e\u5305\u3002\u63a5\u6536\u5230 FIN \u6570\u636e\u5305\u7684\u4e00\u65b9\u4f1a\u53d1\u9001\u4e00\u4e2a ACK \u6570\u636e\u5305\u4ee5\u786e\u8ba4\u6536\u5230 FIN \u6570\u636e\u5305\uff0c\u7136\u540e\u4e5f\u53ef\u80fd\u53d1\u9001\u4e00\u4e2a FIN \u6570\u636e\u5305\u6765\u8868\u793a\u53cc\u65b9\u90fd\u5df2\u5b8c\u6210\u6570\u636e\u4f20\u8f93\u3002\u6b64\u8fc7\u7a0b\u79f0\u4e3a "\u56db\u6b21\u6325\u624b"\uff08Four-way Handshake\uff09\u3002\n\n\u56db\u6b21\u6325\u624b\u7684\u6b65\u9aa4\u5982\u4e0b\uff1a\n\n\u53d1\u9001\u65b9\u53d1\u9001\u4e00\u4e2a FIN \u6570\u636e\u5305\uff0c\u8868\u793a\u5df2\u5b8c\u6210\u6570\u636e\u4f20\u8f93\uff0c\u8bf7\u6c42\u5173\u95ed\u8fde\u63a5\u3002\n\u63a5\u6536\u65b9\u6536\u5230 FIN \u6570\u636e\u5305\u540e\uff0c\u56de\u590d\u4e00\u4e2a ACK \u6570\u636e\u5305\uff0c\u786e\u8ba4\u6536\u5230 FIN \u6570\u636e\u5305\u3002\n\u63a5\u6536\u65b9\u5728\u5b8c\u6210\u6570\u636e\u4f20\u8f93\u540e\uff0c\u4e5f\u4f1a\u53d1\u9001\u4e00\u4e2a FIN \u6570\u636e\u5305\uff0c\u8868\u793a\u5df2\u51c6\u5907\u597d\u5173\u95ed\u8fde\u63a5\u3002\n\u53d1\u9001\u65b9\u6536\u5230\u63a5\u6536\u65b9\u7684 FIN \u6570\u636e\u5305\u540e\uff0c\u56de\u590d\u4e00\u4e2a ACK \u6570\u636e\u5305\uff0c\u786e\u8ba4\u6536\u5230 FIN \u6570\u636e\u5305\u3002\u6b64\u65f6\uff0c\u8fde\u63a5\u88ab\u5173\u95ed\u3002\n\u5728 nmap \u7684\u7aef\u53e3\u626b\u63cf\u4e2d\uff0cFIN \u626b\u63cf\uff08-sF\uff09\u662f\u4e00\u79cd\u4e0d\u6613\u88ab\u68c0\u6d4b\u5230\u7684\u7aef\u53e3\u626b\u63cf\u65b9\u6cd5\u3002FIN \u626b\u63cf\u7684\u539f\u7406\u662f\u53d1\u9001\u4e00\u4e2a FIN \u6570\u636e\u5305\u5230\u76ee\u6807\u4e3b\u673a\u7684\u6307\u5b9a\u7aef\u53e3\u3002\u6309\u7167 TCP \u534f\u8bae\u89c4\u8303\uff0c\u5904\u4e8e\u5173\u95ed\u72b6\u6001\u7684\u7aef\u53e3\u5e94\u8be5\u56de\u590d\u4e00\u4e2a RST \u6570\u636e\u5305\uff0c\u800c\u5904\u4e8e\u5f00\u653e\u72b6\u6001\u7684\u7aef\u53e3\u5e94\u8be5\u5ffd\u7565\u8fd9\u4e2a\u6570\u636e\u5305\u3002\u901a\u8fc7\u89c2\u5bdf\u76ee\u6807\u4e3b\u673a\u7684\u54cd\u5e94\uff0cnmap \u53ef\u4ee5\u5224\u65ad\u7aef\u53e3\u72b6\u6001\u3002\u4e0d\u8fc7\uff0c\u7531\u4e8e\u67d0\u4e9b\u64cd\u4f5c\u7cfb\u7edf\u548c\u9632\u706b\u5899\u7684\u884c\u4e3a\u53ef\u80fd\u4e0e TCP \u534f\u8bae\u89c4\u8303\u4e0d\u4e00\u81f4\uff0cFIN \u626b\u63cf\u7684\u7ed3\u679c\u53ef\u80fd\u4e0d\u5982 SYN \u626b\u63cf\u90a3\u4e48\u53ef\u9760\u3002<\/code><\/pre>\n
                        5.URG\uff08Urgent\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002\u5f53 URG \u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a 1 \u65f6\uff0c\u8868\u793a\u8be5 TCP \u6570\u636e\u5305\u4e2d\u5305\u542b\u7d27\u6025\u6570\u636e\u3002\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0cTCP \u62a5\u5934\u4e2d\u7684\u7d27\u6025\u6307\u9488\u5b57\u6bb5\uff08Urgent Pointer\uff09\u4f1a\u6307\u793a\u7d27\u6025\u6570\u636e\u5728\u6570\u636e\u5305\u4e2d\u7684\u4f4d\u7f6e\u3002\n\nTCP \u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u534f\u8bae\u3002\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u53d1\u9001\u65b9\u53ef\u80fd\u9700\u8981\u53d1\u9001\u7d27\u6025\u6570\u636e\uff0c\u6bd4\u5982\u5728\u8fdc\u7a0b\u767b\u5f55\uff08\u5982 Telnet\uff09\u8fc7\u7a0b\u4e2d\uff0c\u7528\u6237\u5e0c\u671b\u4e2d\u65ad\u6b63\u5728\u8fd0\u884c\u7684\u7a0b\u5e8f\u3002\u8fd9\u65f6\uff0c\u53d1\u9001\u65b9\u53ef\u4ee5\u4f7f\u7528 URG \u6807\u5fd7\u4f4d\u6765\u544a\u8bc9\u63a5\u6536\u65b9\u8be5\u6570\u636e\u5305\u4e2d\u5305\u542b\u7d27\u6025\u6570\u636e\u3002\n\n\u63a5\u6536\u65b9\u5728\u6536\u5230\u8bbe\u7f6e\u4e86 URG \u6807\u5fd7\u4f4d\u7684 TCP \u6570\u636e\u5305\u540e\uff0c\u4f1a\u4f18\u5148\u5904\u7406\u7d27\u6025\u6570\u636e\uff0c\u7136\u540e\u7ee7\u7eed\u5904\u7406\u5176\u4ed6\u6570\u636e\u3002\u8fd9\u79cd\u673a\u5236\u5141\u8bb8 TCP \u5728\u4e0d\u5f71\u54cd\u6b63\u5e38\u6570\u636e\u4f20\u8f93\u7684\u60c5\u51b5\u4e0b\u5904\u7406\u7d27\u6025\u6570\u636e\u3002\n\n\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\uff0cURG \u6807\u5fd7\u4f4d\u548c\u7d27\u6025\u6570\u636e\u7684\u4f7f\u7528\u5e76\u4e0d\u5e38\u89c1\uff0c\u56e0\u4e3a\u73b0\u4ee3\u7f51\u7edc\u5e94\u7528\u901a\u5e38\u4f7f\u7528\u5176\u4ed6\u65b9\u6cd5\u6765\u5904\u7406\u7d27\u6025\u6570\u636e\u6216\u4f18\u5148\u7ea7\u8f83\u9ad8\u7684\u6570\u636e\u3002\u5728 nmap \u7684\u7aef\u53e3\u626b\u63cf\u4e2d\uff0cURG \u6807\u5fd7\u4f4d\u901a\u5e38\u4e0d\u4f1a\u7528\u4e8e\u5224\u65ad\u7aef\u53e3\u72b6\u6001\u3002<\/code><\/pre>\n
                        6.PSH\uff08Push\uff09\u662f TCP\uff08Transmission Control Protocol\uff0c\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7684\u4e00\u4e2a\u6807\u5fd7\u4f4d\u3002\u5f53 PSH \u6807\u5fd7\u4f4d\u88ab\u8bbe\u7f6e\u4e3a 1 \u65f6\uff0c\u8868\u793a\u53d1\u9001\u65b9\u5e0c\u671b\u63a5\u6536\u65b9\u5c3d\u5feb\u5730\u5904\u7406\u8fd9\u4e2a TCP \u6570\u636e\u5305\u4e2d\u7684\u6570\u636e\u3002\u8fd9\u901a\u5e38\u610f\u5473\u7740\u53d1\u9001\u65b9\u8981\u6c42\u63a5\u6536\u65b9\u7acb\u5373\u5c06\u6570\u636e\u4f20\u9012\u7ed9\u4e0a\u5c42\u5e94\u7528\uff0c\u800c\u4e0d\u662f\u7b49\u5f85\u63a5\u6536\u7f13\u51b2\u533a\u88ab\u586b\u6ee1\u6216\u5176\u4ed6\u6761\u4ef6\u6ee1\u8db3\u3002\n\nTCP \u662f\u4e00\u79cd\u9762\u5411\u8fde\u63a5\u7684\u3001\u53ef\u9760\u7684\u6570\u636e\u4f20\u8f93\u534f\u8bae\u3002\u4e3a\u4e86\u63d0\u9ad8\u4f20\u8f93\u6548\u7387\uff0cTCP \u4f1a\u4f7f\u7528\u7f13\u51b2\u533a\u6765\u5b58\u50a8\u53d1\u9001\u548c\u63a5\u6536\u7684\u6570\u636e\u3002\u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u53d1\u9001\u65b9\u53ef\u80fd\u5e0c\u671b\u63a5\u6536\u65b9\u7acb\u5373\u5904\u7406\u67d0\u4e9b\u6570\u636e\uff0c\u800c\u4e0d\u662f\u7b49\u5f85\u7f13\u51b2\u533a\u6ee1\u6216\u5176\u4ed6\u6761\u4ef6\u6ee1\u8db3\u3002\u8fd9\u65f6\uff0c\u53d1\u9001\u65b9\u53ef\u4ee5\u8bbe\u7f6e PSH \u6807\u5fd7\u4f4d\u6765\u8fbe\u5230\u8fd9\u4e2a\u76ee\u7684\u3002\n\n\u5f53\u63a5\u6536\u65b9\u6536\u5230\u8bbe\u7f6e\u4e86 PSH \u6807\u5fd7\u4f4d\u7684 TCP \u6570\u636e\u5305\u65f6\uff0c\u5b83\u4f1a\u5c3d\u5feb\u5c06\u6570\u636e\u4f20\u9012\u7ed9\u4e0a\u5c42\u5e94\u7528\uff0c\u800c\u4e0d\u662f\u7b49\u5f85\u63a5\u6536\u7f13\u51b2\u533a\u88ab\u586b\u6ee1\u3002\u8fd9\u79cd\u673a\u5236\u5141\u8bb8 TCP \u5728\u4fdd\u8bc1\u53ef\u9760\u4f20\u8f93\u7684\u540c\u65f6\uff0c\u6ee1\u8db3\u67d0\u4e9b\u5e94\u7528\u573a\u666f\u4e0b\u7684\u5b9e\u65f6\u6027\u8981\u6c42\u3002\n\n\u5728 nmap \u7684\u7aef\u53e3\u626b\u63cf\u4e2d\uff0cPSH \u6807\u5fd7\u4f4d\u901a\u5e38\u4e0d\u4f1a\u7528\u4e8e\u5224\u65ad\u7aef\u53e3\u72b6\u6001\u3002PSH \u6807\u5fd7\u4f4d\u4e3b\u8981\u7528\u4e8e\u5728 TCP \u6570\u636e\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u63a7\u5236\u6570\u636e\u5904\u7406\u7684\u5b9e\u65f6\u6027\u3002<\/code><\/pre>\n
                        \u4e09\u6b21\u63e1\u624b\u5305\u542b\u7684\u72b6\u6001<\/h2>\n
                        \u5728TCP\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\uff0c\u901a\u4fe1\u53cc\u65b9\uff08\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\uff09\u4f1a\u7ecf\u5386\u4e00\u7cfb\u5217\u72b6\u6001\u53d8\u5316\u3002\u4ee5\u4e0b\u662fTCP\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\u6d89\u53ca\u7684\u4e3b\u8981\u72b6\u6001\uff1a<\/p>\n
                          \n
                        1. CLOSED\uff08\u5173\u95ed\uff09\uff1a \u5728TCP\u8fde\u63a5\u5c1a\u672a\u5efa\u7acb\u6216\u5df2\u7ecf\u7ec8\u6b62\u7684\u60c5\u51b5\u4e0b\uff0c\u901a\u4fe1\u53cc\u65b9\u7684\u72b6\u6001\u4e3aCLOSED\u3002<\/li>\n
                        2. LISTEN\uff08\u76d1\u542c\uff09\uff1a \u670d\u52a1\u5668\u7aef\u5728\u7b49\u5f85\u5ba2\u6237\u7aef\u8fde\u63a5\u8bf7\u6c42\u65f6\uff0c\u8fdb\u5165LISTEN\u72b6\u6001\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u670d\u52a1\u5668\u76d1\u542c\u7279\u5b9a\u7aef\u53e3\uff0c\u7b49\u5f85\u5ba2\u6237\u7aef\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\u3002<\/li>\n
                        3. SYN_SENT\uff08\u540c\u6b65\u5df2\u53d1\u9001\uff09\uff1a \u5f53\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001SYN\u6570\u636e\u5305\u540e\uff0c\u5ba2\u6237\u7aef\u7684\u72b6\u6001\u53d8\u4e3aSYN_SENT\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u5ba2\u6237\u7aef\u7b49\u5f85\u670d\u52a1\u5668\u7684\u54cd\u5e94\u3002<\/li>\n
                        4. SYN_RECEIVED\uff08\u540c\u6b65\u5df2\u6536\u5230\uff09\uff1a \u5f53\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684SYN\u6570\u636e\u5305\u540e\uff0c\u670d\u52a1\u5668\u7684\u72b6\u6001\u53d8\u4e3aSYN_RECEIVED\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u670d\u52a1\u5668\u5df2\u7ecf\u51c6\u5907\u597d\u53d1\u9001SYN+ACK\u6570\u636e\u5305\u7ed9\u5ba2\u6237\u7aef\u3002<\/li>\n
                        5. ESTABLISHED\uff08\u5df2\u5efa\u7acb\uff09\uff1a \u5f53\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684SYN+ACK\u6570\u636e\u5305\uff0c\u5e76\u5411\u670d\u52a1\u5668\u53d1\u9001ACK\u6570\u636e\u5305\u540e\uff0c\u5ba2\u6237\u7aef\u7684\u72b6\u6001\u53d8\u4e3aESTABLISHED\u3002\u540c\u65f6\uff0c\u5f53\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684ACK\u6570\u636e\u5305\u540e\uff0c\u670d\u52a1\u5668\u7684\u72b6\u6001\u4e5f\u53d8\u4e3aESTABLISHED\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0cTCP\u8fde\u63a5\u5df2\u7ecf\u6210\u529f\u5efa\u7acb\uff0c\u901a\u4fe1\u53cc\u65b9\u53ef\u4ee5\u8fdb\u884c\u6570\u636e\u4f20\u8f93\u3002<\/li>\n<\/ol>\n
                          \u4ee5\u4e0b\u662f\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\u7684\u72b6\u6001\u53d8\u5316\u603b\u7ed3\uff1a<\/p>\n
                            \n
                          1. \u5ba2\u6237\u7aef\uff1aCLOSED -> SYN_SENT -> ESTABLISHED<\/li>\n
                          2. \u670d\u52a1\u5668\uff1aCLOSED -> LISTEN -> SYN_RECEIVED -> ESTABLISHED<\/li>\n<\/ol>\n
                            MSL\uff08Maximum Segment Lifetime\uff09\u662f\u6307TCP\u6570\u636e\u5305\u5728\u7f51\u7edc\u4e0a\u5b58\u6d3b\u7684\u6700\u957f\u65f6\u95f4\u3002\u5f53TCP\u534f\u8bae\u5728\u8fdb\u884c\u6570\u636e\u4f20\u8f93\u65f6\uff0c\u6bcf\u4e2a\u6570\u636e\u5305\u90fd\u4f1a\u643a\u5e26\u4e00\u4e2aTTL\uff08Time To Live\uff09\u5b57\u6bb5\uff0c\u7528\u4e8e\u8868\u793a\u6570\u636e\u5305\u5728\u7f51\u7edc\u4e0a\u53ef\u4ee5\u5b58\u6d3b\u7684\u65f6\u95f4\u3002MSL\u662fTCP\u534f\u8bae\u4e2d\u7684\u4e00\u4e2a\u91cd\u8981\u53c2\u6570\uff0c\u5b83\u8868\u793a\u4e00\u4e2aTCP\u6570\u636e\u5305\u5728\u7f51\u7edc\u4e0a\u5b58\u6d3b\u7684\u6700\u957f\u65f6\u95f4\uff0c\u901a\u5e38\u4e3a2\u500d\u7684\u6700\u5927\u5206\u6bb5\u5927\u5c0f\uff08MSS\uff09\u3002\u5728MSL\u65f6\u95f4\u5230\u8fbe\u540e\uff0c\u5982\u679c\u8be5\u6570\u636e\u5305\u4ecd\u672a\u88ab\u63a5\u6536\u65b9\u786e\u8ba4\uff0c\u5219\u8be5\u6570\u636e\u5305\u5c06\u88ab\u7f51\u7edc\u4e22\u5f03\uff0c\u53d1\u9001\u65b9\u9700\u8981\u91cd\u65b0\u53d1\u9001\u6570\u636e\u3002<\/p>\n
                            \u7ecf\u8fc7\u8fd9\u4e2a\u8fc7\u7a0b\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u4e4b\u95f4\u5efa\u7acb\u4e86\u4e00\u4e2a\u53ef\u9760\u7684TCP\u8fde\u63a5\uff0c\u53ef\u4ee5\u8fdb\u884c\u6570\u636e\u4f20\u8f93\u3002\u5f53\u6570\u636e\u4f20\u8f93\u5b8c\u6210\u540e\uff0c\u901a\u4fe1\u53cc\u65b9\u9700\u8981\u901a\u8fc7\u56db\u6b21\u6325\u624b\uff08Four-way Handshake\uff09\u8fc7\u7a0b\u6765\u5173\u95edTCP\u8fde\u63a5\u3002<\/p>\n
                            MSL\u7684\u8bbe\u7f6e\u662f\u4e3a\u4e86\u907f\u514d\u5df2\u5931\u6548\u7684\u6570\u636e\u5305\u5728\u7f51\u7edc\u4e0a\u65e0\u9650\u671f\u5730\u5faa\u73af\uff0c\u6d6a\u8d39\u7f51\u7edc\u8d44\u6e90\u3002\u540c\u65f6\uff0cMSL\u8fd8\u80fd\u4fdd\u8bc1\u8fde\u63a5\u7684\u5b89\u5168\u6027\uff0c\u56e0\u4e3a\u8fde\u63a5\u65ad\u5f00\u540e\u7684\u4e00\u6bb5\u65f6\u95f4\u5185\uff0c\u539f\u6709\u7684\u6570\u636e\u5305\u53ef\u80fd\u4ecd\u7136\u5b58\u5728\u4e8e\u7f51\u7edc\u4e2d\uff0c\u5982\u679c\u8fd9\u4e9b\u6570\u636e\u5305\u88ab\u6076\u610f\u653b\u51fb\u8005\u62e6\u622a\uff0c\u53ef\u80fd\u4f1a\u5bf9\u8fde\u63a5\u9020\u6210\u98ce\u9669\u3002<\/p>\n
                            \u5728TCP\u8fde\u63a5\u65ad\u5f00\u65f6\uff0c\u901a\u5e38\u9700\u8981\u7ecf\u8fc74\u6b21\u63e1\u624b\uff0c\u5176\u4e2d\u6700\u540e\u4e00\u6b21FIN ACK\u62a5\u6587\u6bb5\u88ab\u53d1\u9001\u540e\uff0c\u9700\u8981\u7b49\u5f852\u500dMSL\u7684\u65f6\u95f4\uff0c\u4ee5\u786e\u4fdd\u8fde\u63a5\u4e2d\u6240\u6709\u6570\u636e\u5305\u90fd\u5df2\u7ecf\u88ab\u5b8c\u5168\u63a5\u6536\u548c\u5904\u7406\uff0c\u4ece\u800c\u907f\u514d\u53ef\u80fd\u7684\u6570\u636e\u5305\u91cd\u590d\u548c\u6df7\u4e71<\/p>\n
                            \u4e3a\u4ec0\u4e48\u9700\u8981\u4e24\u500dMSL\u65f6\u95f4\uff1f<\/h3>\n
                            \u6839\u636e\u641c\u7d22\u7ed3\u679c\uff0c\u9700\u8981\u4e24\u500dMSL\u65f6\u95f4\u7684\u539f\u56e0\u6709\u4e24\u4e2a\uff1a<\/p>\n
                              \n
                            • \u786e\u4fdd\u6700\u540e\u4e00\u4e2aACK\u5305\u80fd\u591f\u5230\u8fbe\u88ab\u52a8\u5173\u95ed\u65b9\uff0c\u5982\u679cACK\u5305\u4e22\u5931\uff0c\u88ab\u52a8\u5173\u95ed\u65b9\u4f1a\u91cd\u53d1FIN\u5305\uff0c\u4e3b\u52a8\u5173\u95ed\u65b9\u53ef\u4ee5\u518d\u6b21\u53d1\u9001ACK\u5305\u5e76\u91cd\u65b0\u8ba1\u65f6\u3002<\/li>\n
                            • \u786e\u4fdd\u65e7\u7684TCP\u62a5\u6587\u6bb5\u5728\u7f51\u7edc\u4e0a\u5931\u6548\uff0c\u9632\u6b62\u5b83\u4eec\u5e72\u6270\u65b0\u7684\u8fde\u63a5\u3002\u5982\u679c\u4e0d\u7b49\u5f85\u4e24\u500dMSL\u65f6\u95f4\uff0c\u53ef\u80fd\u4f1a\u51fa\u73b0\u65e7\u7684TCP\u62a5\u6587\u6bb5\u4e0e\u65b0\u7684\u8fde\u63a5\u4f7f\u7528\u76f8\u540c\u7684\u6e90\u5730\u5740\u3001\u6e90\u7aef\u53e3\u3001\u76ee\u6807\u5730\u5740\u548c\u76ee\u6807\u7aef\u53e3\u800c\u5bfc\u81f4\u987a\u5e8f\u6df7\u4e71\u6216\u6570\u636e\u9519\u8bef\u3002<\/li>\n<\/ul>\n
                              \u56db\u6b21\u6325\u624b\u5305\u542b\u7684\u72b6\u6001<\/h2>\n
                              \u56db\u6b21\u6325\u624b\uff08Four-Way Handshake\uff09\u662fTCP\uff08\u4f20\u8f93\u63a7\u5236\u534f\u8bae\uff09\u4e2d\u7528\u4e8e\u5173\u95ed\u4e00\u4e2a\u5df2\u5efa\u7acb\u7684\u8fde\u63a5\u7684\u8fc7\u7a0b\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u6d89\u53ca\u5230\u56db\u4e2a\u6b65\u9aa4\u548c\u56db\u79cd\u72b6\u6001\uff0c\u4ee5\u786e\u4fdd\u53cc\u65b9\u90fd\u80fd\u5b89\u5168\u5730\u5173\u95ed\u8fde\u63a5\u3002\u4ee5\u4e0b\u662f\u56db\u6b21\u6325\u624b\u4e2d\u7684\u56db\u4e2a\u72b6\u6001\uff1a<\/p>\n
                                \n
                              1. \u59cb\u72b6\u6001\uff08ESTABLISHED\uff09: \u5728\u56db\u6b21\u6325\u624b\u5f00\u59cb\u524d\uff0c\u53cc\u65b9\u5904\u4e8e\u5df2\u5efa\u7acb\u8fde\u63a5\u7684\u72b6\u6001\u3002\u6b64\u65f6\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u4e4b\u95f4\u53ef\u4ee5\u8fdb\u884c\u53cc\u5411\u6570\u636e\u4f20\u8f93\u3002<\/li>\n
                              2. FIN_WAIT_1\uff1a\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u5ba2\u6237\u7aef\u4e3b\u52a8\u53d1\u8d77\u5173\u95ed\u8fde\u63a5\u8bf7\u6c42\u3002\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2a\u643a\u5e26FIN\u6807\u5fd7\u4f4d\u7684\u62a5\u6587\u7ed9\u670d\u52a1\u5668\uff0c\u8868\u793a\u5b83\u5df2\u7ecf\u5b8c\u6210\u4e86\u6570\u636e\u53d1\u9001\u3002\u53d1\u9001\u5b8cFIN\u62a5\u6587\u540e\uff0c\u5ba2\u6237\u7aef\u8fdb\u5165FIN_WAIT_1\u72b6\u6001\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u5ba2\u6237\u7aef\u7b49\u5f85\u670d\u52a1\u5668\u7684\u786e\u8ba4\uff08ACK\uff09\u62a5\u6587\u3002<\/li>\n
                              3. CLOSE_WAIT\uff1a\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684FIN\u62a5\u6587\u540e\uff0c\u4f1a\u53d1\u9001\u4e00\u4e2a\u786e\u8ba4\u62a5\u6587\uff08ACK\uff09\u7ed9\u5ba2\u6237\u7aef\u3002\u6b64\u65f6\uff0c\u670d\u52a1\u5668\u5904\u4e8eCLOSE_WAIT\u72b6\u6001\u3002\u670d\u52a1\u5668\u8fd8\u53ef\u4ee5\u7ee7\u7eed\u53d1\u9001\u6570\u636e\u7ed9\u5ba2\u6237\u7aef\uff0c\u4f46\u5df2\u7ecf\u77e5\u9053\u5ba2\u6237\u7aef\u5c06\u4e0d\u518d\u53d1\u9001\u6570\u636e\u3002<\/li>\n
                              4. FIN_WAIT_2\uff1a\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684\u786e\u8ba4\u62a5\u6587\uff08ACK\uff09\u540e\uff0c\u8fdb\u5165FIN_WAIT_2\u72b6\u6001\u3002\u5728\u8fd9\u4e2a\u72b6\u6001\u4e0b\uff0c\u5ba2\u6237\u7aef\u7b49\u5f85\u670d\u52a1\u5668\u53d1\u9001\u5b83\u81ea\u5df1\u7684FIN\u62a5\u6587\uff0c\u4ee5\u8868\u793a\u670d\u52a1\u5668\u5df2\u7ecf\u51c6\u5907\u597d\u5173\u95ed\u8fde\u63a5\u3002<\/li>\n
                              5. LAST_ACK\uff1a\u670d\u52a1\u5668\u5b8c\u6210\u6570\u636e\u53d1\u9001\u540e\uff0c\u4f1a\u53d1\u9001\u4e00\u4e2a\u643a\u5e26FIN\u6807\u5fd7\u4f4d\u7684\u62a5\u6587\u7ed9\u5ba2\u6237\u7aef\u3002\u6b64\u65f6\uff0c\u670d\u52a1\u5668\u8fdb\u5165LAST_ACK\u72b6\u6001\uff0c\u7b49\u5f85\u5ba2\u6237\u7aef\u53d1\u9001\u6700\u540e\u4e00\u4e2a\u786e\u8ba4\u62a5\u6587\uff08ACK\uff09\u3002<\/li>\n
                              6. TIME_WAIT\uff1a\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684FIN\u62a5\u6587\u540e\uff0c\u53d1\u9001\u4e00\u4e2a\u786e\u8ba4\u62a5\u6587\uff08ACK\uff09\u7ed9\u670d\u52a1\u5668\uff0c\u5e76\u8fdb\u5165TIME_WAIT\u72b6\u6001\u3002\u5ba2\u6237\u7aef\u4f1a\u7b49\u5f85\u4e00\u6bb5\u65f6\u95f4\uff08\u901a\u5e38\u662f2\u500d\u7684\u6700\u5927\u62a5\u6587\u6bb5\u751f\u5b58\u65f6\u95f4\uff0c2MSL\uff09\uff0c\u4ee5\u786e\u4fdd\u670d\u52a1\u5668\u6536\u5230\u4e86\u786e\u8ba4\u62a5\u6587\u3002\u8fd9\u4e2a\u7b49\u5f85\u65f6\u95f4\u53ef\u4ee5\u9632\u6b62\u5728\u7f51\u7edc\u4e2d\u5ef6\u8fdf\u7684\u65e7\u62a5\u6587\u5728\u65b0\u8fde\u63a5\u5efa\u7acb\u65f6\u4ea7\u751f\u5e72\u6270\u3002<\/li>\n
                              7. CLOSED\uff1a\u5f53\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684\u6700\u540e\u4e00\u4e2a\u786e\u8ba4\u62a5\u6587\uff08ACK\uff09\u540e\uff0c\u53cc\u65b9\u90fd\u8fdb\u5165CLOSED\u72b6\u6001\u3002\u6b64\u65f6\uff0cTCP\u8fde\u63a5\u5df2\u7ecf\u5b8c\u5168\u5173\u95ed\uff0c\u53cc\u65b9\u53ef\u4ee5\u91ca\u653e\u8d44\u6e90\u3002<\/li>\n<\/ol>\n
                                \u901a\u8fc7\u8fd9\u4e2a\u56db\u6b21\u6325\u624b\u7684\u8fc7\u7a0b\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u53ef\u4ee5\u786e\u4fdd\u53cc\u65b9\u90fd\u6b63\u786e\u5730\u5173\u95ed\u4e86\u8fde\u63a5\uff0c\u907f\u514d\u4e86\u6570\u636e\u4e22\u5931\u6216\u9519\u8bef\u3002<\/p>\n
                                \u4e3a\u4ec0\u4e48tcp\u63e1\u624b\u662f\u4e09\u6b21\uff0c\u4e0d\u662f\u4e24\u6b21\uff1f<\/h2>\n
                                TCP\u91c7\u7528\u4e09\u6b21\u63e1\u624b\u662f\u4e3a\u4e86\u4fdd\u8bc1\u8fde\u63a5\u7684\u53ef\u9760\u6027\u548c\u6b63\u786e\u6027\uff0c\u9632\u6b62\u51fa\u73b0\u4e0d\u5fc5\u8981\u7684\u9519\u8bef\u548c\u91cd\u590d\u6570\u636e\u4f20\u8f93\u3002\u5177\u4f53\u6765\u8bf4\uff0cTCP\u91c7\u7528\u4e09\u6b21\u63e1\u624b\u7684\u539f\u56e0\u5305\u62ec\u4ee5\u4e0b\u51e0\u70b9\uff1a<\/p>\n
                                  \n
                                1. \u9632\u6b62\u5df2\u5931\u6548\u7684\u8fde\u63a5\u8bf7\u6c42\u5230\u8fbe\u670d\u52a1\u5668\uff1a\u5728\u7b2c\u4e00\u6b21\u63e1\u624b\u65f6\uff0c\u5ba2\u6237\u7aef\u5411\u670d\u52a1\u5668\u53d1\u9001SYN\u62a5\u6587\u6bb5\uff0c\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u3002\u5982\u679c\u8be5SYN\u62a5\u6587\u6bb5\u56e0\u7f51\u7edc\u5ef6\u8fdf\u6216\u5176\u4ed6\u539f\u56e0\u957f\u65f6\u95f4\u672a\u88ab\u670d\u52a1\u5668\u6536\u5230\uff0c\u5ba2\u6237\u7aef\u53ef\u80fd\u4f1a\u518d\u6b21\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\u3002\u5982\u679c\u6b64\u65f6\u5ba2\u6237\u7aef\u4e4b\u524d\u53d1\u9001\u7684SYN\u62a5\u6587\u6bb5\u5df2\u7ecf\u5230\u8fbe\u670d\u52a1\u5668\uff0c\u4f46\u5c1a\u672a\u88ab\u670d\u52a1\u5668\u5904\u7406\uff0c\u90a3\u4e48\u670d\u52a1\u5668\u4f1a\u8ba4\u4e3a\u8fd9\u662f\u4e00\u4e2a\u65b0\u7684\u8fde\u63a5\u8bf7\u6c42\uff0c\u8fdb\u800c\u53d1\u9001SYN+ACK\u62a5\u6587\u6bb5\u7ed9\u5ba2\u6237\u7aef\uff0c\u5bfc\u81f4\u8fde\u63a5\u5efa\u7acb\u9519\u8bef\u3002\u91c7\u7528\u4e09\u6b21\u63e1\u624b\u53ef\u4ee5\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\u7684\u53d1\u751f\uff0c\u4fdd\u8bc1\u53ea\u6709\u5408\u6cd5\u7684\u8fde\u63a5\u8bf7\u6c42\u88ab\u5904\u7406\u3002<\/li>\n
                                2. \u786e\u8ba4\u53cc\u65b9\u7684\u63a5\u6536\u548c\u53d1\u9001\u80fd\u529b\uff1a\u5728\u7b2c\u4e8c\u6b21\u63e1\u624b\u65f6\uff0c\u670d\u52a1\u5668\u63a5\u6536\u5230\u5ba2\u6237\u7aef\u53d1\u9001\u7684SYN\u62a5\u6587\u6bb5\uff0c\u8fd4\u56deSYN+ACK\u62a5\u6587\u6bb5\uff0c\u5e76\u4e14\u4e3a\u81ea\u5df1\u7684\u6570\u636e\u5305\u5206\u914d\u4e00\u4e2a\u5e8f\u5217\u53f7\u3002\u6b64\u65f6\u670d\u52a1\u5668\u786e\u8ba4\u81ea\u5df1\u7684\u63a5\u6536\u548c\u53d1\u9001\u80fd\u529b\u90fd\u6b63\u5e38\uff0c\u5ba2\u6237\u7aef\u4e5f\u53ef\u4ee5\u786e\u8ba4\u670d\u52a1\u5668\u7684\u63a5\u6536\u548c\u53d1\u9001\u80fd\u529b\u6b63\u5e38\u3002\u5728\u7b2c\u4e09\u6b21\u63e1\u624b\u65f6\uff0c\u5ba2\u6237\u7aef\u63a5\u6536\u5230\u670d\u52a1\u5668\u53d1\u9001\u7684SYN+ACK\u62a5\u6587\u6bb5\uff0c\u5e76\u4e3a\u81ea\u5df1\u7684\u6570\u636e\u5305\u5206\u914d\u4e00\u4e2a\u5e8f\u5217\u53f7\uff0c\u786e\u8ba4\u81ea\u5df1\u7684\u63a5\u6536\u548c\u53d1\u9001\u80fd\u529b\u6b63\u5e38\uff0c\u540c\u65f6\u4e5f\u786e\u8ba4\u4e86\u670d\u52a1\u5668\u7684\u63a5\u6536\u548c\u53d1\u9001\u80fd\u529b\u6b63\u5e38\u3002<\/li>\n
                                3. \u907f\u514d\u7f51\u7edc\u5ef6\u8fdf\u5bfc\u81f4\u7684\u91cd\u590d\u6570\u636e\u4f20\u8f93\uff1a\u5982\u679c\u91c7\u7528\u4e24\u6b21\u63e1\u624b\uff0c\u5f53\u5ba2\u6237\u7aef\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\u8bf7\u6c42\u5efa\u7acb\u8fde\u63a5\u65f6\uff0c\u7531\u4e8e\u7f51\u7edc\u5ef6\u8fdf\uff0c\u8be5\u62a5\u6587\u6bb5\u53ef\u80fd\u4f1a\u5728\u4e00\u5b9a\u65f6\u95f4\u540e\u624d\u5230\u8fbe\u670d\u52a1\u5668\uff0c\u6b64\u65f6\u670d\u52a1\u5668\u8fd4\u56de\u4e00\u4e2aSYN+ACK\u62a5\u6587\u6bb5\uff0c\u8868\u793a\u63a5\u53d7\u8bf7\u6c42\u3002\u4f46\u662f\u7531\u4e8e\u7f51\u7edc\u5ef6\u8fdf\uff0c\u5ba2\u6237\u7aef\u5e76\u672a\u6536\u5230\u8be5SYN+ACK\u62a5\u6587\u6bb5\uff0c\u800c\u670d\u52a1\u5668\u5374\u8ba4\u4e3a\u8fde\u63a5\u5df2\u7ecf\u5efa\u7acb\u6210\u529f\u3002\u5f53\u5ba2\u6237\u7aef\u518d\u6b21\u53d1\u9001\u4e00\u4e2aSYN\u62a5\u6587\u6bb5\u65f6\uff0c\u7531\u4e8e\u4e4b\u524d\u7684\u8fde\u63a5\u8fd8\u672a\u6b63\u5f0f\u5173\u95ed\uff0c\u670d\u52a1\u5668\u4f1a\u8ba4\u4e3a\u8fd9\u662f\u4e00\u4e2a\u91cd\u590d\u7684\u8fde\u63a5\u8bf7\u6c42\uff0c\u8fd4\u56de\u4e4b\u524d\u5df2\u7ecf\u53d1\u9001\u8fc7\u7684SYN+ACK\u62a5\u6587\u6bb5\uff0c\u5bfc\u81f4\u5ba2\u6237\u7aef\u51fa\u73b0\u91cd\u590d\u6570\u636e\u4f20\u8f93\u7684\u95ee\u9898\u3002\u91c7\u7528\u4e09\u6b21\u63e1\u624b\u53ef\u4ee5\u907f\u514d\u8fd9\u79cd\u60c5\u51b5\u7684\u53d1\u751f\u3002<\/li>\n<\/ol>\n
                                  \u7efc\u4e0a\u6240\u8ff0\uff0cTCP\u91c7\u7528\u4e09\u6b21\u63e1\u624b\u662f\u4e3a\u4e86\u4fdd\u8bc1\u8fde\u63a5\u7684\u53ef\u9760\u6027\u548c\u6b63\u786e\u6027\uff0c\u907f\u514d\u51fa\u73b0\u4e0d\u5fc5\u8981\u7684\u9519\u8bef\u548c\u91cd\u590d\u6570\u636e\u4f20\u8f93\u3002<\/p>\n
                                  \u4e3a\u4ec0\u4e48\u8fd8\u9700\u8981ISN\uff1f<\/h2>\n
                                    \n
                                  1. \u53ef\u9760\u6027\uff1a\u4f7f\u7528ISN+1\u4f5c\u4e3a\u786e\u8ba4\u53f7\u53ef\u4ee5\u786e\u4fdd\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u4e4b\u95f4\u7684\u901a\u4fe1\u662f\u53ef\u9760\u7684\u3002\u5f53\u5ba2\u6237\u7aef\u6536\u5230\u670d\u52a1\u5668\u7684SYN+ACK\u6570\u636e\u5305\u65f6\uff0c\u5b83\u4f1a\u68c0\u67e5\u786e\u8ba4\u53f7\u662f\u5426\u7b49\u4e8e\u5ba2\u6237\u7aef\u53d1\u9001\u7684\u5e8f\u5217\u53f7\u52a01\u3002\u8fd9\u4e2a\u68c0\u67e5\u8fc7\u7a0b\u6709\u52a9\u4e8e\u786e\u4fdd\u8fde\u63a5\u8bf7\u6c42\u548c\u56de\u5e94\u4e4b\u95f4\u7684\u4e00\u81f4\u6027\uff0c\u4ee5\u53ca\u9632\u6b62\u56e0\u7f51\u7edc\u5ef6\u8fdf\u5bfc\u81f4\u7684\u65e7\u6570\u636e\u5305\u88ab\u9519\u8bef\u5730\u63a5\u6536\u3002<\/li>\n
                                  2. \u5b89\u5168\u6027\uff1a\u5728\u7f51\u7edc\u4e2d\uff0c\u53ef\u80fd\u5b58\u5728\u6076\u610f\u653b\u51fb\u8005\u8bd5\u56fe\u4f2a\u9020TCP\u6570\u636e\u5305\uff0c\u4f01\u56fe\u63d2\u5165\u3001\u7be1\u6539\u6216\u8005\u4e2d\u65ad\u8fde\u63a5\u3002\u4f7f\u7528ISN+1\u4f5c\u4e3a\u786e\u8ba4\u53f7\u53ef\u4ee5\u589e\u52a0\u653b\u51fb\u8005\u4f2a\u9020\u5408\u6cd5\u6570\u636e\u5305\u7684\u96be\u5ea6\u3002\u653b\u51fb\u8005\u4e0d\u4ec5\u9700\u8981\u731c\u6d4b\u6b63\u786e\u7684ISN\uff0c\u8fd8\u9700\u8981\u9884\u6d4b\u4e0b\u4e00\u4e2a\u6b63\u786e\u7684\u786e\u8ba4\u53f7\uff0c\u8fd9\u5927\u5927\u964d\u4f4e\u4e86\u653b\u51fb\u7684\u6210\u529f\u51e0\u7387\u3002<\/li>\n<\/ol>\n
                                    \u56e0\u6b64\uff0c\u867d\u7136\u770b\u8d77\u6765\u53ef\u80fd\u6709\u4e9b\u591a\u6b64\u4e00\u4e3e\uff0c\u4f46\u5b9e\u9645\u4e0a\u8fd9\u4e2a\u8bbe\u8ba1\u662f\u4e3a\u4e86\u786e\u4fddTCP\u534f\u8bae\u7684\u53ef\u9760\u6027\u548c\u5b89\u5168\u6027\u3002\u8fd9\u4e5f\u662fTCP\u534f\u8bae\u5728\u6570\u636e\u4f20\u8f93\u8fc7\u7a0b\u4e2d\u80fd\u591f\u63d0\u4f9b\u53ef\u9760\u6027\u4fdd\u8bc1\u7684\u4e00\u4e2a\u5173\u952e\u56e0\u7d20\u3002<\/p>\n
                                    SYN\u6709\u4ec0\u4e48\u7528\uff1f<\/h2>\n
                                    SYN\uff08Synchronize Sequence Numbers\uff0c\u540c\u6b65\u5e8f\u5217\u7f16\u53f7\uff09\u662fTCP\u534f\u8bae\u4e2d\u7684\u4e00\u4e2a\u63a7\u5236\u4f4d\uff08flag\uff09\uff0c\u7528\u4e8e\u5728\u5efa\u7acb\u8fde\u63a5\u8fc7\u7a0b\u4e2d\u540c\u6b65\u901a\u4fe1\u53cc\u65b9\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff08ISN\uff09\u3002SYN\u6807\u5fd7\u4f4d\u5728\u4e09\u6b21\u63e1\u624b\u8fc7\u7a0b\u4e2d\u8d77\u5230\u5173\u952e\u4f5c\u7528\uff0c\u5b83\u6709\u5982\u4e0b\u7528\u9014\uff1a<\/p>\n
                                      \n
                                    1. \u5efa\u7acb\u8fde\u63a5\uff1a\u5f53\u5ba2\u6237\u7aef\u60f3\u8981\u4e0e\u670d\u52a1\u5668\u5efa\u7acbTCP\u8fde\u63a5\u65f6\uff0c\u5b83\u4f1a\u53d1\u9001\u4e00\u4e2aSYN\u6570\u636e\u5305\uff0c\u5176\u4e2dSYN\u6807\u5fd7\u4f4d\u8bbe\u4e3a1\uff0c\u8868\u660e\u8fd9\u662f\u4e00\u4e2a\u8fde\u63a5\u8bf7\u6c42\u3002\u540c\u65f6\uff0c\u5ba2\u6237\u7aef\u4e3a\u8fde\u63a5\u751f\u6210\u4e00\u4e2a\u521d\u59cb\u5e8f\u5217\u53f7\uff08ISN\uff09\u3002\u901a\u8fc7\u8fd9\u4e2aSYN\u6570\u636e\u5305\uff0c\u5ba2\u6237\u7aef\u544a\u77e5\u670d\u52a1\u5668\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff0c\u5e76\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\u3002<\/li>\n
                                    2. \u54cd\u5e94\u8fde\u63a5\u8bf7\u6c42\uff1a\u5f53\u670d\u52a1\u5668\u6536\u5230\u5ba2\u6237\u7aef\u7684SYN\u6570\u636e\u5305\u540e\uff0c\u5982\u679c\u540c\u610f\u5efa\u7acb\u8fde\u63a5\uff0c\u5b83\u4f1a\u53d1\u9001\u4e00\u4e2aSYN+ACK\u6570\u636e\u5305\u3002\u5728\u8be5\u6570\u636e\u5305\u4e2d\uff0cSYN\u6807\u5fd7\u4f4d\u4e5f\u8bbe\u4e3a1\uff0c\u8868\u793a\u670d\u52a1\u5668\u540c\u610f\u5efa\u7acb\u8fde\u63a5\u3002\u540c\u65f6\uff0c\u670d\u52a1\u5668\u4e3a\u8be5\u8fde\u63a5\u751f\u6210\u81ea\u5df1\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff0c\u5e76\u5c06\u5ba2\u6237\u7aef\u7684\u5e8f\u5217\u53f7\u52a01\u4f5c\u4e3a\u786e\u8ba4\u53f7\uff08ACK Number\uff09\u3002\u8fd9\u6837\uff0c\u5ba2\u6237\u7aef\u548c\u670d\u52a1\u5668\u5c31\u4ea4\u6362\u4e86\u5404\u81ea\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff0c\u5e76\u786e\u8ba4\u53cc\u65b9\u5df2\u7ecf\u51c6\u5907\u597d\u5efa\u7acb\u8fde\u63a5\u3002<\/li>\n
                                    3. \u786e\u4fdd\u552f\u4e00\u6027\uff1aSYN\u6570\u636e\u5305\u4e2d\u7684\u521d\u59cb\u5e8f\u5217\u53f7\u662f\u968f\u673a\u751f\u6210\u7684\u3002\u8fd9\u6837\u505a\u662f\u4e3a\u4e86\u786e\u4fdd\u6bcf\u6b21\u5efa\u7acb\u7684TCP\u8fde\u63a5\u90fd\u5177\u6709\u552f\u4e00\u6027\uff0c\u9632\u6b62\u56e0\u7f51\u7edc\u5ef6\u8fdf\u7b49\u539f\u56e0\u9020\u6210\u7684\u8fc7\u671f\u8fde\u63a5\u8bf7\u6c42\u88ab\u9519\u8bef\u5730\u63a5\u53d7\u3002<\/li>\n<\/ol>\n
                                      \u603b\u4e4b\uff0cSYN\u6807\u5fd7\u4f4d\u5728TCP\u8fde\u63a5\u5efa\u7acb\u8fc7\u7a0b\u4e2d\u53d1\u6325\u7740\u81f3\u5173\u91cd\u8981\u7684\u4f5c\u7528\u3002\u5b83\u7528\u4e8e\u540c\u6b65\u901a\u4fe1\u53cc\u65b9\u7684\u521d\u59cb\u5e8f\u5217\u53f7\uff0c\u53d1\u8d77\u8fde\u63a5\u8bf7\u6c42\uff0c\u5e76\u5728\u670d\u52a1\u5668\u7aef\u786e\u8ba4\u8fde\u63a5\u3002\u901a\u8fc7\u8fd9\u4e2a\u673a\u5236\uff0cTCP\u534f\u8bae\u786e\u4fdd\u4e86\u8fde\u63a5\u7684\u53ef\u9760\u6027\u548c\u6570\u636e\u4f20\u8f93\u7684\u5b8c\u6574\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
                                      TCP\u4e09\u6b21\u63e1\u624b\u3001\u56db\u6b21\u6325\u624b TCP\uff08Transmission Control Protocol\uff09\u662f\u4e00\u79cd […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[38],"tags":[39],"views":206,"_links":{"self":[{"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/posts\/347"}],"collection":[{"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/8.141.4.74\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=347"}],"version-history":[{"count":1,"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/posts\/347\/revisions"}],"predecessor-version":[{"id":348,"href":"http:\/\/8.141.4.74\/index.php?rest_route=\/wp\/v2\/posts\/347\/revisions\/348"}],"wp:attachment":[{"href":"http:\/\/8.141.4.74\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=347"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/8.141.4.74\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=347"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/8.141.4.74\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=347"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}