套接字编程：常见错误 - 端口权限

Socket Programming: Common Error - Port Privileges

套接字编程：常见错误 - 端口权限

Issue

When attempting to set up a server socket to listen on a port, received an error: “Failed to listen on port 111”.

问题

尝试设置服务器套接字以监听端口时，收到错误：“无法监听端口111”。

Cause

The error was caused by attempting to bind a socket to a port that requires elevated privileges. In most operating systems, ports numbered below 1024 are considered “privileged” and can only be bound to by processes with root or administrator privileges.

原因

此错误是由于尝试将套接字绑定到需要提升权限的端口所致。在大多数操作系统中，编号低于1024的端口被视为“特权”端口，只能由具有根或管理员权限的进程绑定。

Solution

Use a port number greater than 1024 for non-privileged applications. This avoids the need for root privileges and is generally a best practice for most applications.

解决方案

对于非特权应用程序，使用大于1024的端口号。这样可以避免需要根权限，并且通常是大多数应用程序的最佳实践。

Example

Instead of using port 111, use a higher port number like 5000, 8000, or any other above 1024.

示例

不要使用端口111，而应使用更高的端口号，如5000、8000或任何其他超过1024的端口。

int port = 5000; // A non-privileged port
if (!communicator.listenOnPort(port)) {
    std::cerr << "Failed to listen on port " << port << std::endl;
    // Handle error
}

int port = 5000; // 一个非特权端口
if (!communicator.listenOnPort(port)) {
    std::cerr << "监听端口 " << port << " 失败" << std::endl;
    // 处理错误
}

Additional Notes

• Security Practices: Using non-privileged ports is also a good security practice, as it minimizes the risk associated with running applications with elevated privileges.
• Checking Port Availability: Before binding to a port, ensure it’s not already in use by another process. Tools like netstat on Linux/Mac or Resource Monitor on Windows can be used to check port availability.

补充说明

• 安全实践：使用非特权端口也是一种良好的安全实践，因为它最大限度地减少了运行具有提升权限的应用程序的风险。
• 检查端口可用性：在绑定到端口之前，请确保它未被其他进程使用。可以使用Linux/Mac上的netstat或Windows上的资源监视器等工具检查端口的可用性。