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Re: EPSV vs PASV

From: Leo <leo.r_at_rogers.com>
Date: Mon, 24 Jan 2011 14:58:48 -0500

On 1/20/11 8:58:48 AM, Daniel Stenberg wrote:
> On Thu, 20 Jan 2011, Michael Wood wrote:
>
>>> < 425 Data connection already open.
>>
>> OK, so the server thinks there's nothing wrong with EPSV, but libcurl
>> couldn't connect, so when libcurl retried with PASV, the server says
>> "Hey! What are you doing? You already asked me to open a port for
>> EPSV and now you want me to open another one for PASV???"
>>
>> I think the only way libcurl can deal with this is to close the
>> control channel after the EPSV failed and then open a new one when
>> trying the PASV. Unless maybe an ABOR command would work. But, first
>> try the latest version of libcurl, because it might already do
>> something like this. I have not checked.
>
> You're right, after the failed connect I suppose libcurl needs to do
> either an ABOR or a complete close, and it doesn't do any of that now
> even in the current version.
>
> However, judging from that output, it wouldn't completely solve this
> issue as it takes 75 seconds to fail anyway. That failure seems to be
> network-related (like a firewall) and just about the only way to avoid
> that problem is to not even try EPSV...
>
Daniel and Michael:

Thanks a lot for getting to the bottom of it! I'll get back to this
topic soon when a few crazy days are over. :)

Leo
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Received on 2011-01-24