This solution addresses the issue of network connectivity problems in macOS caused by system proxy failure, which prevents the Terminal and IDEs (such as VS Code and IntelliJ) from connecting to the internet. It provides a complete network troubleshooting and configuration solution, covering manual settings for environment variables `http_proxy` and `https_proxy`, techniques for persisting shell configuration files (zshrc/bash_profile), and proxy plugin configurations for different IDEs. It is suitable for developers who need to access remote repositories such as GitHub, PyPI, or Maven through a proxy, and focuses on resolving synchronization issues between system-level and application-level proxies.