Cache / Proxy¶
Proxies are intermediaries that sit between clients and servers. A client connects to a proxy, and then the proxy decides if the client can receive content from a server. If so, the proxy makes its own connection to the server and then passes back data to the client.
There are two major types of proxies:
- Forward Proxy
Typically sits between local clients and remote Internet servers. It can be used to control which web sites that clients are allowed to load, or log servers and URLs clients are visiting. These mostly work with HTTP, but in special cases can also work with HTTPS.
- Reverse Proxy
Typically sits between remote clients and local servers. These allow for load balancing, failover, or other intelligent connection routing for public services such as web servers.
Squid is primarily a forward proxy used for client access control. It can, however, be used in a reverse proxy role if needed. The reverse proxy capabilities are inferior to HAProxy, however.
The most common use case for squid is covered in Configuring the Squid Package as a Transparent HTTP Proxy. Additional documentation below covers related topics.