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Software components for data protection, secure storage and transfer

Shutting Down Ipswitch ssh service

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Create virtual disks backed by memory or custom location, expose disk images as disks and more.
#4532
Posted: 12/18/2007 18:09:06
by Darren McDowell (Standard support level)
Joined: 11/29/2006
Posts: 3

We are using version 5.2, every time we download a file over 2 megs, my I.T. guy states that we are shutting down the ipswitch ssh service, and shutting down the server.

I am just wondering if other people have experienced this issue.
#4535
Posted: 12/19/2007 06:54:59
by Eugene Mayevski (EldoS Corp.)

Just a guess - try setting PipelineLength property to 1. Maybe IPSwitch server doesn't unnderstand pipelining and the default value of 32 packets causes it to crash with overflow of internal buffers.


Sincerely yours
Eugene Mayevski
#4538
Posted: 12/19/2007 08:51:12
by Darren McDowell (Standard support level)
Joined: 11/29/2006
Posts: 3

Na, still getting the same thing. it states SFTP error 105, and then shuts down our service. It does get about 8000 bytes through the file.
#4540
Posted: 12/19/2007 08:57:19
by Ken Ivanov (EldoS Corp.)

Remember that you also need to set AutoAdjustTransferBlock to false to make TElSimpleSFTPClient use PipelineLength value.
#7992
Posted: 10/30/2008 09:43:28
by Morris Schneider (Basic support level)
Joined: 10/29/2008
Posts: 1

Quote
Darren McDowell wrote:
We are using version 5.2, every time we download a file over 2 megs, my I.T. guy states that we are shutting down the ipswitch ssh service, and shutting down the server.

I am just wondering if other people have experienced this issue.


Exactly the same thing is happening to our IpSwitch server (WS_FTP 6.1) when I transfer larger files using the SBB client. So I tried transferring the 2.4MB file with another client (FileZilla) and compared the server logs of the failed and successful transfers. I found SBB using "c_MaxPacket: 262144" and FileZilla using "c_MaxPacket: 16384".

I traced the MaxPacket number 262144 to a constant, IN_BUFFER_SIZE, in SBSSHConstants.pas. It is used (in SBSSHCommon.pas) to set the SSH input buffer length and the FMaxSSHPacketSize (in SBSSHClient.pas). So I made a small modification to SBSSHConstants and set IN_BUFFER_SIZE = 16384. Then my SBB client worked. I was able to download files any size (the largest I tried was 37MB).

Obviously the IpSwitch server has a bug. It shouldn’t crash just because it can’t handle the large SSH packet size. But I do need a workaround, so I plan to leave the IN_BUFFER_SIZE at the small number. Is that a safe thing to do? Are there any consequences I should be aware of? Why does the IN_BUFFER_SIZE / FMaxSSHPacketSize default to value that is too large for some servers?



Server Log Excerpts - 1st crashes SSH server, 2nd works

Received client version: SSH-2.0-EldoS.SSHBlackbox.5]]
....
SFTP subsystem started in channel s_Id: 46, c_Id: 0, c_Window: 32749, c_MaxPacket: 262144, s_Window: 300000, s_MaxPacket: 30000

Received client version: SSH-2.0-PuTTY_FZ_Local:_May_14_2006_19:26:51
....
SFTP subsystem started in channel s_Id: 49, c_Id: 256, c_Window: 16365, c_MaxPacket: 16384, s_Window: 300000, s_MaxPacket: 30000
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Cross-platform protocol-independent communication framework for building peer-to-peer and client-server applications and middleware components.

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