First of all, the amount of information provided by the questioner is too small for me to judge the problem. It is best to give the code and operating environment, but I can give you two tips: 1. Windows is in application When the program listens to a non-loopback port, a firewall prompt will pop up. If you click No without paying attention, there will be no prompt in the future, and the listening port will fail silently. Only deleting the firewall rule or renaming the file will be useful. 2. If you are making HTTP requests through http.sys, such as HttpClient, and listening to a non-loopback address, you need administrator rights to run it. If it is indeed http.sys and you don’t want to run it with administrator privileges, you can download this tool and add the port you want to monitor: http://httpsysmanager.codeplex.com/
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First of all, the amount of information provided by the questioner is too small for me to judge the problem. It is best to give the code and operating environment, but I can give you two tips:
1. Windows is in application When the program listens to a non-loopback port, a firewall prompt will pop up. If you click No without paying attention, there will be no prompt in the future, and the listening port will fail silently. Only deleting the firewall rule or renaming the file will be useful.
2. If you are making HTTP requests through http.sys, such as HttpClient, and listening to a non-loopback address, you need administrator rights to run it.
If it is indeed http.sys and you don’t want to run it with administrator privileges, you can download this tool and add the port you want to monitor:
http://httpsysmanager.codeplex.com/