Hi Daniel, Thanks for the prompt reply. It was that 2003 e-mail that prompted me to ask these questions! You have confirmed what I feared. I thought in all these years, something may have changed but you are right, FTP is hardly on the rise. Unfortunately, I will have to hack something up (perhaps option 1) because I need it in an embedded system for "backwards compatibility".
I trimmed the response somewhat, preserving your conclusions. Thanks for clarifying, Carlos On Wed, Nov 23, 2016 at 2:35 AM, Daniel Stenberg <[email protected]> wrote: > On Wed, 23 Nov 2016, Carlos Rimola wrote: > > 1) What form of FTP Proxy (servers) does Libcurl support? (RFCs?). Any >> specific examples like ftp-proxy or squid? >> > > Amusingly enough, I answered almost this question already 13 years ago: > https://curl.haxx.se/mail/archive-2003-04/0120.html > > Strictly speaking, there's no formal support for proxy in the FTP protocol > at all. There are not RFCs for that and there's not even any proper > informal standards. > > There are three ways to do proxying with FTP: > > 1 - abuse the existing FTP protocol but send data in "wrong" fields. Like > pass in the actual remote host name as user: > > ftp://user%40remotehost:password@ftpproxyhost/path/to/remote/file > > 2 - just ask for a FTP:// URL over a HTTP proxy and hope for the best > > 3 - tunnel through a HTTP proxy with *PROXYTUNNEL which makes libcurl use > CONNECT - this kind of operation is often blocked by HTTP proxies. > > is not Libcurl's issue but mainly the weak definition of FTP Proxy in the >> RFCs? However RFC-1919 ("Classical versus Transparent IP Proxies") seems to >> clear much of how to make FTP proxies operate. >> > > RFC 1919 is over 20 years old and I can agree that it discusses how > connections work for proxies but it certainly does not detail enough how an > FTP proxy should work or be used by a client such as curl. > > I think people have managed to get pass with the above methods so nobody > ever implemented support for other for further ftp-proxies. FTP is hardly a > protocol on the rise these days which I suppose also helps explain the lack > of interest. > > -- > > / daniel.haxx.se > ------------------------------------------------------------------- > List admin: https://cool.haxx.se/list/listinfo/curl-library > Etiquette: https://curl.haxx.se/mail/etiquette.html
------------------------------------------------------------------- List admin: https://cool.haxx.se/list/listinfo/curl-library Etiquette: https://curl.haxx.se/mail/etiquette.html
