正向代理和反向代理

While a forward proxy acts as an intermediary for its associated clients to contact any server, a reverse proxy acts as an intermediary for its associated servers to be contacted by any client.

 爲 client 作代理

 爲 server 作代理

Reverse proxies can hide the existence and characteristics of an origin server or servers.

反向代理能夠隱藏原始服務

Application firewall features can protect against common web-based attacks, such as DOS or DDOS. Without a reverse proxy, removing malware or initiating takedowns, for example, can become difficult.

應用防火牆特性能夠抵禦基於網絡的攻擊，好比拒絕服務或者分佈式拒絕服務。

In the case of secure websites, a web server may not perform SSL encryption itself, but instead offloads the task to a reverse proxy that may be equipped with SSL acceleration hardware. (See SSL termination proxy.)

對於安全站點，服務器自己可能不會執行SSL加密，而是把該任務交給配備了SSL加速硬件的反向代理服務器。

A reverse proxy can distribute the load from incoming requests to several servers, with each server serving its own application area. In the case of reverse proxying in the neighborhood of web servers, the reverse proxy may have to rewrite the URL in each incoming request in order to match the relevant internal location of the requested resource.

反向代理能夠把請求壓力分發到多態服務器，須要重寫URL來匹配請求資源的正確的內部地址。

A reverse proxy can reduce load on its origin servers by caching static content, as well as dynamic content - also known as web acceleration. Proxy caches of this sort can often satisfy a considerable number of website requests, greatly reducing the load on the origin server(s).

反向代理能夠經過緩存靜態內容和動態內容來削減原始服務器的壓力，被稱之爲網絡加速。

A reverse proxy can optimize content by compressing it in order to speed up loading times.

反向代理能夠經過壓縮提速

In a technique known as "spoon-feed"[2] a dynamically generated page can be produced all at once and served to the reverse-proxy, which can then return it to the client a little bit at a time. The program that generates the page need not remain open, thus releasing server resources during the possibly extended time the client requires to complete the transfer.

服務器能夠一次性把頁面給反向代理，反向代理能夠一點一點的返回給client。

Reverse proxies can operate whenever multiple web-servers must be accessible via a single public IP address. The web servers listen on different ports in the same machine, with the same local IP address or, possibly, on different machines and different local IP addresses altogether. The reverse proxy analyzes each incoming request and delivers it to the right server within the local area network.

。。。