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Re: Implicit SSL connections doesn't works

From: Daniel Stenberg <>
Date: Thu, 30 Aug 2007 14:02:49 +0200 (CEST)

On Thu, 30 Aug 2007, Abel Alonso wrote:

> I detect the problem and it was that the curl library doesn't send the PROT
> P command.

No way. When you connect with implicit FTPS to a site, it connects with SSL
*immediately* so there's no chance to send any commands before the SSL
negotiations happen.

So it *did* manage to connect and perform various commands? Wow, you should
really consider sharing some info with us if you want our help...

> I've change the curl source code to force to send the command and it works,
> but i suppose that is not a well solution

It's a solution that we should consider. The current libcurl assumes that when
you do implicit FTPS you use encrypted data transfers too so it doesn't send
any PROT command.

Doing PROT P would fix this issue for the servers that don't do the same
assumption and should be fine with those that do. Although implicit FTPS is
kind of "the old way" of doing FTPS so servers that speak it are old and not
really following recent standards so erratic and unpredictable behaviour is to
be expected when this route is selected...

I'll be interested in your patch!

> No. I mean that without put the :990 into the url it doesn't work. All
> explicit connections work well on 21 port.

Explicit FTPS is using ftp:// URLs and they are supposed to be on port 21 (by
default). In fact, using explicit ftps on port 990 is very unusual and I would
say it indicates that either you or me is confusing implicit/explicit...

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Received on 2007-08-30