Dedicated Proxy Or Proxy Server | Part 3
Other Application Scenarios Of A Reverse Proxy
There are several reasons for using a reverse proxy:
Network Security
The reverse proxy is another link in the security chain, and thus contributes to the security of web servers.
Single Sign-On
The reverse proxy can accept user authentication for multiple web servers. Thus the user only needs to register once to use the services of several servers.
Encryption / SSL acceleration
If secure web pages are created, the SSL encryption is not uncommon done by the web server itself, but by a reverse proxy that is equipped with a corresponding acceleration hardware. Thus, it is also possible to use a (SSL) Certificate to use on the proxy (rather than behind it on a web server). For Squid (version 2.6) to do this is via software.
By relocating the encryption on the proxy to achieve the following benefits:
- The web server is through the removal of the encryption (possibly considerably relieved).
- The proxy can cache the web content, which otherwise would not be possible and represents a further reduction of the web server.
- ACLs can be applied to encrypted sites, since the proxy provides for the header in the clear.
Load balancing
The reverse proxy can distribute the load across multiple servers, each server uses its field of application. In paraphrase, the reverse proxy web server where the URLs in each web page (translation of the externally known URLs to the internal sites).
Caching of content
A reverse proxy can reduce the burden on Web servers by caching static content like images and the results are often of called dynamically generated pages (for scripting). In this way, a significantly higher number can be dealt with on site queries.
In case of failure of the underlying web server (or in case of failure: for example, HTTP 500) is also a “friendly” message to be displayed.
Furthermore, a reverse proxy can also be used as an open proxy to send requests to “its name” to foreign servers, without this being intended by the operator so. Therefore, it may be advisable to configure it so that it responds only to requests to specific servers. As an example, this happens when Squid by a rule http_access allow for <acl server> behind it with the final rule http_access deny ave
The web browser requests through a proxy derive
There are several ways to access the browser through a proxy to derive:
Environment
Some browsers, such as Lynx cost, an environment variable (in this case ‘http_proxy =’) and then use the entered value, unless it is empty.
Direct Configuration
Here are the name (or IP address) of the proxy server and port to which he hears, entered directly in the browser. The disadvantage is that you must do this manually for each client and changes it nachzutragen individually on each client.
Transparent Proxy
Here is configured on the clients anything they submit their requests to the destination on port 80 (HTTP), as if they had a direct connection to the Internet. The infrastructure of the network ensures that their requests are routed to the proxy.
Automatic proxy configuration (Proxy Auto-Config)
Here is entered in the browser the URL of a Java script that address and port of the proxy server returns. If this work is done once, further changes are made centrally in the script. The script can also assign a reverse proxy.
Web Proxy Auto Discovery Protocol (WPAD)
This is a protocol with the Web client as a browser to use automated web proxies can be found within a computer network by using a Proxy Auto-Config (PAC) file in a guessable URL is stored, for example: http://wpad. example.com / wpad.dat
Possible issues when using a proxy
Hazards:
A poorly configured proxy can be dangerous, since it enables third parties to act on the address of the proxy on the Internet. As an example, the proxy for an attack, or – like an open mail relay could – be used to send spam. When abuse is then identified as the source of the proxy, which may may have unpleasant consequences for the operator.
Statistics of hits:
Especially commercial server, the advertising space for rent to justify their attractiveness for advertising with traffic, the statistics generated by the web server. Proxy servers and filters affect these numbers, of course negative, as appears from the cache content is not delivered there, and a portion of advertising is not even loaded. Some vendors of web sites today are trying to make their content difficult or impossible to cacheable.
As a proxy anonymizer:
In various Internet forums, as well as the Wikipedia, is the creation or modification of articles about open proxy servers are often prevented by blocking the appropriate IP addresses to complicate an anonymous participation. It makes sense, this is often done only for non-registered users.
Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.
