Direct Proxy:
In Direct proxy the proxy server configuration is manually configured in the browser.This type of proxy is used mainly is schools and colleges.In this type of proxy authentication methods can be used to access the proxy.
Transparent Proxy:
In Transparent proxy server configuration the client is unaware of the proxy server and client needs no configuration to detect the proxy.
Reverse Proxy:
In Reverse proxy configuration the squid is used as a accelerator for the webserver.
Transparent Tproxy:
The transparent tproxy is a feature which helps in client IP spoofing and this method also does not require any configuration in the client side.