Proxy Server and Configuration

What is a proxy server? How do I get proxy server information? 

(An intermediary between your home machine and the rest of the computers on the internet).

A proxy server is an intermediary computer that is between the user's computer and the Internet. It can be used to log Internet usage and also to block access to a web site. The firewall at the proxy server blocks some web sites or web pages for various reasons. As a result, you may be unable to download Java Runtime Environment (JRE) or to run some Java applets.
Proxy servers:

• Act as a firewall and content filter
  A security mechanism deployed by the ISP's or network administrators in an Intranet environment to disable access or filter content requests to certain web sites considered offensive or harmful for the network and users.
• Improve performance
  Caches (stores) web pages accessed by hosts on the network for a certain amount of time. Whenever any host requests the same web page, the proxy server uses the cached information instead of retrieving it from the content provider. This leads to quicker access of the web pages.

Getting Proxy Server Information

Check with your Internet Service Provider (ISP) or system administrator:

• To get proxy server information
• If Java applets are disabled to run on your network
• If you are trying to access a blocked web site 

In an enterprise that uses the Internet, a proxy server is a server that acts as an intermediary between a workstation user and the Internet so that the enterprise can ensure security, administrative control, and caching service. A proxy server is associated with or part of a gateway server that separates the enterprise network from the outside network and a firewall server that protects the enterprise network from outside intrusion.

A proxy server receives a request for an Internet service (such as a Web page request) from a user. If it passes filtering requirements, the proxy server, assuming it is also a cache server , looks in its local cache of previously downloaded Web pages. If it finds the page, it returns it to the user without needing to forward the request to the Internet. If the page is not in the cache, the proxy server, acting as a client on behalf of the user, uses one of its own IP addresses to request the page from the server out on the Internet. When the page is returned, the proxy server relates it to the original request and forwards it on to the user.

To the user, the proxy server is invisible; all Internet requests and returned responses appear to be directly with the addressed Internet server. (The proxy is not quite invisible; its IP address has to be specified as a configuration option to the browser or other protocol program.)
An advantage of a proxy server is that its cache can serve all users. If one or more Internet sites are frequently requested, these are likely to be in the proxy's cache, which will improve user response time. In fact, there are special servers called cache servers. A proxy can also do logging.
The functions of proxy, firewall, and caching can be in separate server programs or combined in a single package. Different server programs can be in different computers. For example, a proxy server may in the same machine with a firewall server or it may be on a separate server and forward requests through the firewall.

A server that sits between a client application, such as a Web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request to the real server.

Proxy servers have two main purposes:

Improve Performance: Proxy servers can dramatically improve performance for groups of users. This is because it saves the results of all requests for a certain amount of time. Consider the case where both user X and user Y access the World Wide Web through a proxy server. First user X requests a certain Web page, which we'll call Page 1. Sometime later, user Y requests the same page. Instead of forwarding the request to the Web server where Page 1 resides, which can be a time-consuming operation, the proxy server simply returns the Page 1 that it already fetched for user X. Since the proxy server is often on the same network as the user, this is a much faster operation. Real proxy servers support hundreds or thousands of users. The major online services such as America Online, MSN and Yahoo, for example, employ an array of proxy servers.

Filter Requests: Proxy servers can also be used to filter requests. For example, a company might use a proxy server to prevent its employees from accessing a specific set of Web sites. 

  A Proxy

Most internet browsers can be setup to run through proxies in just a matter of minutes.

Internet Explorer Proxy Settings

• Click Tools
• Click Internet Options
• Click the Connections Tab
• Click LAN settings
• Check the “Use a proxy server for your LAN” box
• Enter the IP Address of the Proxy Server and the Port Number
• Click OK
• Go to WhatIsMyIP.com to check for proxy

FireFox Proxy Settings

• Click the FireFox Button(The button in the upper left corner)
• Click Options
• Click Options in the new tab
• Click the Advanced Tab
• Click Settings
• Click Manual Proxy Settings
• In the HTTP Proxy Box enter the IP Address of the proxy server and the Port number
• Click OK
• Go to WhatIsMyIP.com to check for proxy

Google Chrome Proxy Settings

• Click the Customize and Control Button(Button with the wrench picture in upper right corner
• Click Under the Hood
• Click Change proxy settings
• Click LAN Settings
• Check the “Use a proxy server for your LAN” box
• Enter the IP Address of the Proxy Server and the Port Number
• Click OK
• Go to WhatIsMyIP.com to check for proxy

Safari Proxy Settings

• Click Safari
• Click Preferences
• Click Advanced
• Click Change Settings
• Check the Web Proxy(HTTP) box
• Enter the IP Address of the Proxy Server and the Port Number
• Click Apply Now
• Go to WhatIsMyIP.com to check for proxy

Proxy Detection

Are you truly hidden? We do provide proxy detection at WhatIsMyIP.com. If your proxy is setup correctly you will see it’s IP address on the homepage and you may receive a message that a proxy was detected. It is impossible to detect all proxies. We may not detect your proxy but that does not mean that other sites can’t.

How do I configure proxy settings for Java? 

Proxy settings for running applets can be controlled through the Java Control Panel.

Find the Java Control Panel

Windows XP

• Click on the Start button and then click on the Control Panel option.
• Double click on the Java icon to open the Java Control Panel.

Windows 7, Vista

• Click on the Start button and then click on the Control Panel option.
• In the Control Panel Search enter Java Control Panel.
• Click on the Java icon to open the Java Control Panel.

Windows 8
Use search to find the Control Panel

• Press Windows logo key + W to open the Search charm to search settings
  OR
  Drag the Mouse pointer to the bottom-right corner of the screen, then click on the Search icon.
• In the search box enter Java Control Panel
• Click on Java icon to open the Java Control Panel.

Mac OS X 10.7.3 and above

• Click on Apple icon on upper left of screen.
• Go to System Preferences
• Click on the Java icon to access the Java Control Panel.
  
  

Configure Proxies through the Java Control Panel

1. In the Java Control Panel, click on Network Settings, located under the General tab.
2. Select the Use Browser Settings checkbox.
3. Click OK to save your changes.
   
   
4. Close all browser windows. Restart the browser and try to load the applet.
5. If the applet still does not load and you see the same connection error, try to configure your web browser's proxy settings.

Common Error if Proxy is not set

A common error that is seen if the proxy settings are not correct:

 
While application is starting, a dialog like this appears including "ClassNotFoundException"

General Exception

Name: JavaAppplication

ClassNotFoundException: JavaAppplication.class