X-Recipient: archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status: No, hits=0.7 required=5.0	tests=AWL,BAYES_00,KAM_BADIPHTTP,NORMAL_HTTP_TO_IP,T_RP_MATCHES_RCVD,WEIRD_PORT
X-Spam-Check-By: sourceware.org
MIME-Version: 1.0
Content-Type: text/plain;	charset="us-ascii"
x-cr-puzzleid: {F597541D-DE39-44E4-9D1B-84797D4AD681}
x-cr-hashedpuzzle: HMU= AbMO BZUK CEh/ Ccfu CqMh DVjB FuyX HgLe H1d0 IzR8 JRBa Jc3i JhNn Jyh0 J6PP;1;YwB5AGcAdwBpAG4AQABjAHkAZwB3AGkAbgAuAGMAbwBtAA==;Sosha1_v1;7;{F597541D-DE39-44E4-9D1B-84797D4AD681};bQBpAGMAaABhAGUAbAAuAHcAaQBlAGQAbQBhAG4AbgBAAGEAYQBzAHQAcgBhAC4AYwBvAG0A;Fri, 06 Jan 2012 13:42:26 GMT;QwB5AGcAaQB3AG4AJwBzACAAcwBzAGgAZAAsACAAMgAgAHQAdQBuAG4AZQBsAHMAIABhAG4AZAAgAGYAaQBsAGUAIAB0AHIAYQBuAHMAZgBlAHIAIABmAGEAaQBsAHMA
Content-class: urn:content-classes:message
Subject: Cygiwn's sshd, 2 tunnels and file transfer fails
Date: Fri, 6 Jan 2012 14:42:26 +0100
Message-ID: <F5F6578C2B51B1469FE9A7A17315C8B7028D6F86@bermail01.de.aastra.com>
From: "Michael Wiedmann" <michael DOT wiedmann AT aastra DOT com>
To: <cygwin AT cygwin DOT com>
X-IsSubscribed: yes
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Note-from-DJ: This may be spam
Content-Transfer-Encoding: 8bit
X-MIME-Autoconverted: from quoted-printable to 8bit by delorie.com id q06DgsEp028332

Given the following test scenario:

 +-----------+         +-----------------+           +-----------+
 | Client #1 |         |  Server (XP/7)  |           | Client #2 |
 | - ssh     |   1)    |   Cygwin/sshd   |   2), 3)  | - ssh     |
 | - httpd   +-------->+                 +<----------+           |
 +-----------+         |                 |           +-----------+    
                       +-----------------+

1) client #1 initiates a ssh connection to cygwin/sshd _and_
   requests "remote port forwarding" like:
   -R 60000:client_#1_ip:80 server_ip

   This works w/o any problems

2) client #2 initiates a ssh connection to cygwin/sshd _and_
   requests "local port forwarding" like:
   -L 1234:127.0.0.1:60000 server_ip
   
   This works w/o any problems

3) client #2 accesses httpd on client #1 using 127.0.0.1:1234

   This works for "simple" web browsing

   But if client #2 tries to upload "large" files, e.g. like:

   curl -X PUT -d @file.txt http://127.0.0.1:1234/uploaddir/file.txt

   to client #1's httpd this fails after transferring only a small
   part of the file.

   The ssh connection itself is not affected and stays intact.

   It looks like the TCP congestion/overload control mechanism of the 
   two TP streams does not work properly in this case.

Testing the same scenario using a Linux sshd this works w/o any
problems.

Is this a known problem of Cygwin?

Any known workaround?


--
Problem reports:       http://cygwin.com/problems.html
FAQ:                   http://cygwin.com/faq/
Documentation:         http://cygwin.com/docs.html
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple