HTTP Authentication and Proxy Configurations

HTTP Authentication Since the reverse proxy server masquerades as a Web server, the authentication required by the reverse proxy is Web server authentication. That is, the challenge status code is 401, not 407. See elsewhere in this blog for HTTP authentication, and differences between Web server and proxy server authentication.

Dynamic Content and Reverse Proxying

Dynamic content poses a problem With reverse proxies. If the content is dynamically generated, it cannot be cached efficiently. Rather, each request must be forwarded to the origin server. This defeats the benefits of caching in the proxy server, and may in fact impede performance. A common misconception relates to the way CGI scripts are handled. CGI scripts are always executed by the origin server; they are never trans- ferred in their source code/program language form to the proxy server and executed there. Only the result of the CGI execution is passed to the proxy server, and, if marked cacheable, it may be cached by the proxy. As long as the number of dynamic pages is fairly small compared to the total number of requests, reverse proxying can be beneficial as in this case – If there are many dynamic pages, they may be duplicated on multiple origin servers, and DNS round robin used to distribute the load among them. The static content may still be handled by reverse proxy servers.

Alternatives to Using Reverse Proxies:

There are a couple of alternatives to reverse proxies. One is the 3 05 Use Proxy status code in HTTP/ 1.1 that is intended for redirecting the client [or an intermediate (forward) proxy] that directly connects to the origin server to go through a proxy server. This releases the proxy in question from having to be a reverse proxy, since the client is now aware of the proxy’s existence in between. The 305 status code is intended as a mechanism for associating a one-site—only proxy server that will not be used for anything else. Note that if a (forward) proxy server is already used by the client, the client will not receive the 305 response. Instead, it is intercepted and handled by the last (forward) proxy in the proxy chain (that’s the proxy that attempted a direct connection to the origin server to begin with).

At the time of this writing, the support for the 305 status code is not widespread, either by client software or proxy servers. Once HTTP/1 becomes more widespread, the use of 305 proxy redirection may be viable option to reverse proxying. Another alternative to reverse proxying is to handle replication ~ ‘ server content by other means.

This can be accomplished by a plugin, the Web server, or by copying content between servers by other too such as FTP or secure rdist. At this time, copying content between servers using out-of-band mechanisms is the most common way of ting up large server pools. As reverse proxy server technology advance» may become an easier mechanism for setting up server pools. SUMMARY Reverse proxying provides an alternative to moving the server from ‘ internal network to the firewall. As the performance of proxy server \ ” ware increases, they may become a viable solution for synchronizing among multiple replicated servers in a large origin server pool.

Source: Guidance on Find a Fast UK Proxy

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