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[Moderator Action] FTP and the REIN commmand

From: Peter Stamfest <peter.stamfest@eunet.at>
Date: Wed, 16 Aug 2000 03:33:28 -0400 (EDT)
To: www-lib@w3.org
Message-ID: <Pine.LNX.4.21.0008160849410.25174-100000@peter.stamf.pr.at>


I am experiencing problems with the HTFTP module.

The problem is as follows:

The first access to a FTP server works OK, however, any further access
fails. I have traced the problem to the REIN command used by HTFTP. The
problem, however, is much more fundamental:

libwww seems to reuse its connections based on host/port information
only. It does not take user information into account. If FTP would blindly
reuse such a channel, it might be the case that it uses wrong user
information for the access. To avoid this, HTFTP wants to reinitialize the
(open) FTP session using the REIN command. With most FTP servers, this
seems to fail (at least it fails with wu-ftpd), and HTFTP bails out.

I think there are two solutions to this problem: 

1.) Do not reuse FTP connections!
2.) Put some user information into the persistent connection cache
    (see HTHost_new in HTHost.c). Maybe there should be some
    protocol specific "extrad information" associated with each
    persistent connection (together with a comparison callback), so 
    that a high level protocol can refuse to use an existing channel!
    Something like this seem to exists, given the existance of

Are there any other possibilities?


Peter Stamfest                    UNIX, Networking & Computing Consultant
Tel: +43/699/20711205             Software Development
E-Mail: ps@psncc.at               WWW: http://www.psncc.at/
Received on Wednesday, 16 August 2000 03:34:06 UTC

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