https://blog.witd.in/tags/udp/ Recent content in Udp on 备忘 Hugo -- gohugo.io en-us kongfei605@gmail.com (kongfei) kongfei605@gmail.com (kongfei) (c) 2022 witd. All rights reserved Sat, 19 Aug 2023 21:45:10 +0800 https://blog.witd.in/2023/08/19/udp%E7%AB%AF%E5%8F%A3%E6%8E%A2%E6%B4%BB/ Sat, 19 Aug 2023 21:45:10 +0800 kongfei605@gmail.com (kongfei) https://blog.witd.in/2023/08/19/udp%E7%AB%AF%E5%8F%A3%E6%8E%A2%E6%B4%BB/ <h1 id="一-背景">一 背景</h1> <p>商业客户反馈用<code>categraf</code>的<code>net_response</code>插件配置了<code>udp</code>探测, 遇到报错了，如图 <img src="https://blog.witd.in/images/udp_port_scanning/error.png" alt="error.png" /></p> <p>udp是无连接的，无法用建立连接的形式判断端口。 插件最初的设计是需要配置udp的发送字符，并且配置期望返回的字符串，</p> <pre><code>[[instances]] targets = [ &quot;127.0.0.1:161&quot;, ] protocol = &quot;udp&quot; ## string sent to the server send = &quot;hello&quot; ## expected string in answer expect = &quot;hello&quot; </code></pre> <p>通过返回字符与期望字符是否相等，来判断端口是否连通。用户随即发了另一张图 ，用ncat 来探测端口是ok的 <img src="https://blog.witd.in/images/udp_port_scanning/ncat.png" alt="ncat.png" /> </p>