https://blog.wenb.in/tags/%E6%8A%93%E5%8C%85/ Recent content in 抓包 on WWayne's Blog Hugo zh-CN Wed, 18 May 2011 00:00:00 +0000 https://blog.wenb.in/posts/2011-05-18_wireshark%E9%94%99%E8%AF%AFheaderchecksum0x0000incorrectsh/ Wed, 18 May 2011 00:00:00 +0000 https://blog.wenb.in/posts/2011-05-18_wireshark%E9%94%99%E8%AF%AFheaderchecksum0x0000incorrectsh/ <p>Wireshark抓主机自身的包时，某些情况下会发现IP包头中出现如标题所示的错误提示。</p> <p>原因如下：<br> a lot of modern network cards use TCP/IP checksum o<!-- more -->ffloading, in which case Windows doesn&rsquo;t bother generating a checksum for each outbound packet and the network card adds them just before transmission.<br> This reduces the amount of work that the computer&rsquo;s CPU has to do, but the problem is that Wireshark can only intercept packets at the OS level, and hence thinks the checksums are invalid (when in fact the problem is that they haven&rsquo;t been added yet).</p>