Reference Manual

NAME

wpad - interact with the Web Proxy Auto-Discovery mechanisms

wpad [dns  [fname | on | off]]
wpad [dhcp [url   | on | off]]

 Execute...

Network administrators sometimes require that web clients use a proxy server to access the Web. Web Proxy Auto-Discovery enables web clients to obtain a proxy configuration file that specifies the name of a web proxy and how that proxy should be used.

Two discovery methods are commonly used:

• The most common method consists of a web client issuing a DNS request for the name wpad.domain. NAT32's DNS resolver can respond to that request in a way that enables the client to access the file fname that contains the needed proxy configuration information. The file is typically named either proxy.pac or wpad.dat and must be located in NAT32's HTM directory.

• The second method uses the DHCP protocol to inform the client machine of a URL from which the needed configuration information can be loaded. The URL is returned to the client via Option 252 in DHCP REQUEST and INFORM datagrams.

The two forms of the wpad command allow one or both of the methods to be enabled or disabled.

The WPAD mechanism should be used with caution, because once a web client has been configured to use a proxy, it will continue to do so until told otherwise. Should the Internet connection change for any reason, the proxy may become unreachable and web access will be disrupted.

The default proxy.pac and wpad.dat files configure web clients to use NAT32's HTTPD.

WPAD Protocol, proxy.pac, wpad.dat, HTTPD