Re: [squid-users] FTP over squid

On Friday 12 September 2003 14.25, Abdul Khader wrote:
> Hi,
> Thanks for everyone's help. I am grateful to all of
> you. But, can anyone explain why do the documentation
> of squid speak about ftp.

Read my previous response again:

HTTP proxies can operate on ftp:// URLs when requested to do so by
HTTP clients, but HTTP proxies are NOT FTP proxies.

The main difference between what is a HTTP proxy and what is a FTP
proxy (apart from quite different functionality) is in what protocol
is used between the client and the proxy. In case of a HTTP proxy the
HTTP protocol is used between the client and the proxy and the client
can ask the proxy via HTTP to operate on basically any kind of URL
but with the semantics of the HTTP protocol.

In case of FTP proxies the client talks FTP to the proxy using any of
the FTP proxy models (user@host etc), and the proxy can normally only
operate on FTP objects with the semantics of the FTP protocol.

Additions to make the above clearer:

The fact that a HTTP client may ask a HTTP proxy to operate on
basically any kind of URL includes asking the HTTP proxy to operate
on ftp:// URLs. Squid supports operations on http://, ftp:// and
gopher:// URLs via the HTTP proxy when asked to do so by HTTP
clients.

HTTP clients is any program who talks the HTTP potocol to the proxy.
This includes all web browsers with support for proxy settings, and
most commanline HTTP clients (via http/ftp/gopher_proxy environment
variables or configuration) and very the few ftp clients with support
for HTTP proxies (which technically makes the ftp client no longer an
ftp client but a http client looking much like a ftp client to the
user).

Regards
Henrik

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