PAC File Documentation

Overview

Feature Value
File Extension .pac
MIME Type application/x-ns-proxy-autoconfig
Primary Use Proxy server configuration
Content Format JavaScript functions
Main Function FindProxyForURL(url, host)
Secondary Functions dnsResolve(host), myIpAddress(), etc.
Return Values PROXY, SOCKS, DIRECT
Configuration Flexibility High
Execution Environment Web browser or system network settings
Advantages Dynamic proxy selection, customizable
Limitations Depends on JavaScript interpreter, potential security concerns
Common Usage Large organizations, Educational institutions
Security Practices Use HTTPS for downloading PAC files, Validate PAC file content
Modification Text editor or specialized tools
Support in Browsers Widely supported
File Location Web server or local filesystem
Example Use Case Load balancing between multiple proxies
Compatibility Cross-platform
Deployment Manual configuration or scripts
Accessibility Publicly accessible URL or internal network location
Update Mechanism Replace file on server or client machine