Setting Up Clients To Use a Proxy

Clients (currently Mosaic 2.2 and Lynx 2.3, and newer) can be set up to connect to the outside world through proxies by setting the following environment variables:

http_proxy
ftp_proxy
gopher_proxy
wais_proxy

to URLs of a cern_httpd running as a proxy.

Example of a Script Starting Up a Client

    #!/bin/sh
    http_proxy="http://your.proxy.server:8080/";   export http_proxy
    ftp_proxy="http://your.proxy.server:8080/";    export ftp_proxy
    gopher_proxy="http://your.proxy.server:8080/"; export gopher_proxy
    wais_proxy="http://your.proxy.server:8080/";   export wais_proxy
    exec Mosaic

Often the file: URL is used as an ftp: URL, so it might be appropriate to set also the file_proxy environment variable. However, beware that this does not work with all the client programs yet! See also how httpd can be configured to do proxying for file: URLs.

These environment variables affect also W3C httpd itself when it's running as a proxy, that is, the proxy will use another proxy to access remote servers instead of connecting to them directly. This is the intended behaviour since there are times when a connection to the outside world has to be made through two proxies. However, it can sometimes be also a source of confusion, if e.g. proxy environment variables are set in one's .cshrc (or such) file, and one then starts proxy by hand.

no_proxy

Some clients support the no_proxy environment variable that specifies a set of domains for which the proxy should not be consulted; the contents is a comma-separated list of domain names, with an optional :port part:

        no_proxy="cern.ch,ncsa.uiuc.edu,some.host:8080"
	export no_proxy

httpd@w3.org, July 1995