<div class="__aliyun_email_body_block"><div style="font-family: Tahoma, Arial, STHeitiSC-Light, SimSun"><div style="clear: both; font-family: Tahoma, Arial, STHeitiSC-Light, SimSun;"><span ><span ><br ></span></span></div><div style="clear: both; font-family: Tahoma, Arial, STHeitiSC-Light, SimSun;"><span ><span >After executing the nc command twice, executing the nc command again timed out, and the netstat command showed that the server did not close the socket connection：</span></span></div><div style="clear: both; font-family: Tahoma, Arial, STHeitiSC-Light, SimSun;"><span ><br ></span></div><div style="clear: both; font-family: Tahoma, Arial, STHeitiSC-Light, SimSun;"><span ><span >[root@172-26-51-207 ~]# systemctl status usbredir-4100-003-002.service </span></span><div style="clear: both;">● usbredir-4100-003-002.service - /sbin/usbredirserver -p 4100 003-002</div><div style="clear: both;"> Loaded: loaded (/run/systemd/transient/usbredir-4100-003-002.service; transi></div><div style="clear: both;">Transient: yes</div><div style="clear: both;"> Active: active (running) since Tue 2025-05-13 14:13:41 CST; 12min ago</div><div style="clear: both;"> Main PID: 3864277 (usbredirserver)</div><div style="clear: both;"> Tasks: 2 (limit: 101063)</div><div style="clear: both;"> Memory: 608.0K</div><div style="clear: both;"> CGroup: /system.slice/usbredir-4100-003-002.service</div><div style="clear: both;"> └─3864277 /sbin/usbredirserver -p 4100 003-002</div><div style="clear: both;">5月 13 14:13:41 172-26-51-207 systemd[1]: Started /sbin/usbredirserver -p 4100 ></div><div ><span >5月 13 14:13:45 172-26-51-207 usbredirserver[3864277]: usbredirparser: Peer ver></span></div><div ><span ><br ></span></div></div><div style="clear: both; font-family: Tahoma, Arial, STHeitiSC-Light, SimSun;"><span ><span >[root@172-26-51-207 ~]# rpm -qa | grep usb</span></span><div style="clear: both;">qemu-kvm-hw-usbredir-6.2.0-232.g09252161d1.el8.x86_64</div><div style="clear: both;">usbredir-0.12.0-2.el8.x86_64</div><div style="clear: both;">libusbx-1.0.23-4.el8.x86_64</div><div style="clear: both;">usbutils-010-3.el8.x86_64</div><div style="clear: both;">usbredir-server-0.12.0-2.el8.x86_64</div><div style="clear: both;">libgusb-0.3.0-1.el8.x86_64</div><div style="clear: both;">[root@172-26-51-207 ~]# nc -zv 172.26.51.207 4100</div><div style="clear: both;">Ncat: Version 7.70 ( <a href="https://nmap.org/ncat" target="_blank">https://nmap.org/ncat</a> )</div><div style="clear: both;">Ncat: Connected to 172.26.51.207:4100.</div><div style="clear: both;">Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.</div><div style="clear: both;">[root@172-26-51-207 ~]# netstat -nap | grep 4100</div><div style="clear: both;">tcp 0 0 172.26.51.207:47988 172.26.51.207:4100 FIN_WAIT2 - </div><div style="clear: both;">tcp6 1 0 :::4100 :::* LISTEN 3864277/usbredirser </div><div style="clear: both;">tcp6 1 0 172.26.51.207:4100 172.26.51.207:47988 CLOSE_WAIT - </div><div style="clear: both;">tcp6 0 0 172.26.51.207:4100 172.26.51.230:58576 ESTABLISHED 3864277/usbredirser </div><div style="clear: both;">[root@172-26-51-207 ~]# nc -zv 172.26.51.207 4100</div><div style="clear: both;">Ncat: Version 7.70 ( <a href="https://nmap.org/ncat" target="_blank">https://nmap.org/ncat</a> )</div><div style="clear: both;">Ncat: Connected to 172.26.51.207:4100.</div><div style="clear: both;">Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.</div><div style="clear: both;">[root@172-26-51-207 ~]# netstat -nap | grep 4100</div><div style="clear: both;">tcp 0 0 172.26.51.207:47988 172.26.51.207:4100 FIN_WAIT2 - </div><div style="clear: both;">tcp 0 0 172.26.51.207:33384 172.26.51.207:4100 FIN_WAIT2 - </div><div style="clear: both;">tcp6 2 0 :::4100 :::* LISTEN 3864277/usbredirser </div><div style="clear: both;">tcp6 1 0 172.26.51.207:4100 172.26.51.207:33384 CLOSE_WAIT - </div><div style="clear: both;">tcp6 1 0 172.26.51.207:4100 172.26.51.207:47988 CLOSE_WAIT - </div><div style="clear: both;">tcp6 0 0 172.26.51.207:4100 172.26.51.230:58576 ESTABLISHED 3864277/usbredirser </div><div style="clear: both;">[root@172-26-51-207 ~]# nc -zv 172.26.51.207 4100</div><div style="clear: both;">Ncat: Version 7.70 ( <a href="https://nmap.org/ncat" target="_blank">https://nmap.org/ncat</a> )</div><div ><span >Ncat: Connection timed out.</span></div><span ><br ></span></div></div></div> <article class="4ever-article" data-clipboard-cangjie="["root",{},["p",{"bdr":{"bottom":{"color":"#000000","space":0,"sz":0,"val":"none"},"left":{"color":"#000000","space":0,"sz":0,"val":"none"},"right":{"color":"#000000","space":0,"sz":0,"val":"none"},"top":{"color":"#000000","space":0,"sz":0,"val":"none"}},"ind":{"firstLine":0,"left":0,"right":0},"jc":"left","keepLines":false,"keepNext":false,"rPr":{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei"},"highlight":"#FFFF00","italic":false,"kern":0,"spacing":0,"sz":10,"szUnit":"pt"},"spacing":{"after":"0pt","afterAutospacing":false,"before":"0pt","beforeAutospacing":false,"line":1,"lineRule":"auto"},"windowControl":true},["span",{"data-type":"text"},["span",{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei"},"highlight":"#FFFF00","spacing":0,"kern":0,"sz":10,"szUnit":"pt","data-type":"leaf"},"此信件包含保密信息，请收件人予以保密，未经许可，请勿向第三人披露，谢谢。"]]],["p",{"bdr":{"bottom":{"color":"#000000","space":0,"sz":0,"val":"none"},"left":{"color":"#000000","space":0,"sz":0,"val":"none"},"right":{"color":"#000000","space":0,"sz":0,"val":"none"},"top":{"color":"#000000","space":0,"sz":0,"val":"none"}},"ind":{"firstLine":0,"left":0,"right":0},"jc":"left","keepLines":false,"keepNext":false,"rPr":{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei"},"italic":false,"kern":0,"spacing":0,"sz":10,"szUnit":"pt"},"spacing":{"after":"0pt","afterAutospacing":false,"before":"0pt","beforeAutospacing":false,"line":1,"lineRule":"auto"},"windowControl":true},["span",{"data-type":"text"},["span",{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei","hint":"eastAsia"},"spacing":0,"kern":0,"sz":10,"szUnit":"pt","data-type":"leaf"},"（微软雅黑，14"],["span",{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei","hint":"default"},"spacing":0,"kern":0,"sz":10,"szUnit":"pt","data-type":"leaf"},"px"],["span",{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"microsoft yahei","cs":"microsoft yahei","eastAsia":"microsoft yahei","hAnsi":"microsoft yahei","hint":"eastAsia"},"spacing":0,"kern":0,"sz":10,"szUnit":"pt","data-type":"leaf"},"）"]]],["p",{"bdr":{"bottom":{"color":"#000000","space":0,"sz":0,"val":"none"},"left":{"color":"#000000","space":0,"sz":0,"val":"none"},"right":{"color":"#000000","space":0,"sz":0,"val":"none"},"top":{"color":"#000000","space":0,"sz":0,"val":"none"}},"ind":{"firstLine":0,"left":0,"right":0},"jc":"left","keepLines":false,"keepNext":false,"rPr":{"caps":false,"color":"#000000","fonts":{"ascii":"Tahoma","cs":"Tahoma","eastAsia":"Tahoma","hAnsi":"Tahoma","hint":"default"},"highlight":"#FFFF00","italic":false,"spacing":0,"sz":11,"szUnit":"pt"},"spacing":{"after":"0pt","afterAutospacing":false,"before":"0pt","beforeAutospacing":false,"line":1.31,"lineRule":"atLeast"},"windowControl":true},["span",{"data-type":"text"},["span",{"caps":false,"color":"#A5A5A5","fonts":{"ascii":"Times New Roman","cs":"Times New Roman","eastAsia":"Tahoma","hAnsi":"Times New Roman"},"highlight":"#FFFF00","spacing":0,"kern":0,"sz":11,"szUnit":"pt","data-type":"leaf"},"This letter contains confidential information which is requested to be kept confidential by the recipient and shall not be disclosed to any third party without permission. Thank you."]]]]"><p style="text-align: left; text-indent: 0px; margin-left: 0px; margin-top: 0px; margin-bottom: 0px;"><span style="color: rgb(165, 165, 165); font-family: "microsoft yahei", "microsoft yahei", "microsoft yahei", "microsoft yahei";">此信件包含保密信息，请收件人予以保密，未经许可，请勿向第三人披露，谢谢。</span><br></p><div style="text-align: left; text-indent: 0px; margin-left: 0px; margin-top: 0px; margin-bottom: 0px; line-height: 1.5em;"><span style="color: rgb(165, 165, 165); background-color: rgb(255, 255, 255); font-family: "times new roman"; font-size: 14px;">This letter contains confidential information which is requested to be kept confidential by the recipient and shall not be disclosed to any third party without permission. Thank you.</span></div></article><div style="clear: both;"><br></div>