Polipo will usually fetch instances directly from source servers as this configuration minimises latency. In some cases, however, it may be useful to have Polipo fetch instances from a parent proxy.
The variable parentHost
specifies the hostname or IP address of
a parent proxy; Polipo will contact this proxy using the port number
specified by parentPort
.
If the parent proxy requires authorisation, the username and password
should be specified in the variable parentAuthCredentials
in
the form username:password
. Only Basic authentication
is supported, which is vulnerable to replay attacks.
The main application of the parent proxy support is to cross
firewalls. Given a machine, say trurl
, with unrestricted
access to the web, the following evades a firewall by using an
encrypted compressed ssh
link:
$ ssh -f -C -L 8124:localhost:8123 trurl polipo $ polipo parentHost=localhost parentPort=8124