Printable View
Whenever I want to find what proxy my browser uses, I have to navigate each and every PC connected on the network. I want to ask - is there any automated tool through which I can tell my browser what proxy it can use ?
Any ideas.....please give your suggestions
thank you
I would like to suggest you about the tool called WPAD
WPAD means Web Proxy Auto-Discovery Protocol
The Web Proxy Auto Discovery Protocol, WPAD for short, simply does what its name implies.
An application connecting to the internet may search the local network to find information about proxies and rules which proxy to use when connecting to specific (i.e. local or remote) servers. WPAD leverages a JavaScript file called wpad.dat that is located on a WPAD server. The file itself is retrieved using HTTP. WPAD has been implemented by Netscape in 1996 has not changed much since then.
Basically there are two ways for an application to detect the URL to the WPAD server -
- There is a DHCP option that tells DHCP clients where wpad.dat can be found on a network. By virtue of DHCP this information is only available to DHCP clients. The DHCP option 252 can be used to return an URL to the wpad.dat file. Note that URLs specifying non-standard ports are also possible.
- The other way to retrieve the wpad.dat script is to do a DNS lookup for a host named WPAD and do a HTTP GET for /wpad.dat on this host. The DNS option, however, provides less information to the client application because it only specifies the server and has no way of transmitting information about the HTTP port to the client.
The Web Proxy Autodiscovery Protocol (WPAD) is a method used by clients to locate a proxy auto-config file automatically and use this to configure the browser's web proxy settings.
WPAD was created by Microsoft and first included with Internet Explorer 5.0; this implementation is commonly referred to by the name "Autoproxy".
It was submitted to the IETF for standardization in 1999, but the draft expired and no standardization activity has occurred since.
Nevertheless, Internet Explorer and other major browsers such as Mozilla Firefox retain this functionality.
In order for all browsers in an organization to be supplied the same proxy policy, without configuring each browser manually, both the below technologies are required -
Proxy auto-config (PAC) standard - create and publish one central proxy configuration file.
Web Proxy Autodiscovery Protocol (WPAD) standard - ensure that an organization's browsers will find this file without manual configuration.
The WPAD standard defines two alternative methods the system administrator can use to publish the location of the proxy configuration file,
- Dynamic Host Configuration Protocol (DHCP)
- Domain Name System (DNS)
Requirements - In order for WPAD to work, a few requirements have to be met.
- In order to use DHCP, the server must be configured to serve up the "site-local" option 252 ("auto-proxy-config") with a string value of "http://xxx.yyy.zzz.qqq/wpad.dat" (without the quotes) where xxx.yyy.zzz.qqq is the address of a web server (either IP or DNS).
- In order to use DNS, then a DNS entry is needed for a host named WPAD.
- The host WPAD must be able to serve a web page.
- In both cases, the web server must be configured to set up dat files with a MIME type of "application/x-ns-proxy-autoconfig".
- The file named wpad.dat must be located in the WPAD web site's root directory.
- Examples for PAC files are shown in Proxy auto-config.
- Use caution when configuring a WPAD server in a virtual hosting environment. When automatic proxy detection is used, Internet Explorer sends a "Host: <IP address>" header and Firefox sends a "Host: wpad" header. This is unexpected behavior, therefore, it is recommended that the wpad.dat file be hosted under the default Virtual Host rather than its own.
- Internet Explorer version 6.0.2900.2180.xpsp_sp2_rtm request for "wpad.da" instead of wpad.dat" to the web server.