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TElSimpleSFTPClient : Connection Lost (error code is 0)

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#13570
Posted: 06/01/2010 15:41:08
by Scott Byam (Standard support level)
Joined: 05/28/2010
Posts: 9

Hi Eugene.

Your suggestion has worked, however it does not work consistently. When I first added the code below to the sample project it worked. However the next 3-4 attempts it failed (with the same error message I was getting originally), then worked once again, followed by another 3-4 failures:

////Disable newer algorithms.
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_FIRST, false);
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_DH_GROUP_14, false);
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_DH_GROUP_EXCHANGE256, false);
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_LAST, false);

////Enable older algorithms.
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_DH_GROUP, true);
this.SftpClient.set_KexAlgorithms(SBSSHConstants.Unit.SSH_KEX_DH_GROUP_EXCHANGE, true);

Do you know why there would be intermittent successes surrounded by failures.

Thank you.
#13573
Posted: 06/02/2010 00:52:28
by Eugene Mayevski (EldoS Corp.)

I suggest that you contact the authors of the server and ask them why their server behaves in such a strange way. This is obviously a bug of the server, and spending time on workarounds is not the best idea, as it doesn't help fix the original issues.


Sincerely yours
Eugene Mayevski
#13574
Posted: 06/02/2010 01:26:56
by Eugene Mayevski (EldoS Corp.)

We can do it the following way: try to connect to the server using CuteFTP application (it produces a nice log). Be sure to enable maximum logging level in it. If the connection is successful, please post the log here -- we will see what algorithms are accepted by the server.


Sincerely yours
Eugene Mayevski
#13576
Posted: 06/02/2010 10:47:44
by Scott Byam (Standard support level)
Joined: 05/28/2010
Posts: 9

Hi Eugene,

Here is the information from the CUTE FTP log that you requested:

Allowed encryption method(s) by user:
3des-cbc
arcfour
cast128-cbc
twofish-cbc
blowfish-cbc
twofish128-cbc
aes128-cbc
aes256-cbc
----------------------------
Allowed MAC algorithms method(s) by user:
hmac-md5
hmac-sha1
hmac-sha1-96
hmac-md5-96

I don't think it is their server as I am able to connect to their server with no problems with other SFTP clients such as Ipswitch (and CUTE FTP).

I will take a stab at what the above algorithms map to in terms of ELDOS algorithms. What is the "CTR" stand for in terms of an algorithm name i.e. SSH_EA_TWOFISH128 vs. SSH_EA_TWOFISH128_CTR

Thank you.
#13577
Posted: 06/02/2010 11:27:49
by Scott Byam (Standard support level)
Joined: 05/28/2010
Posts: 9

Eugene,

Would you have any idea on your end what twofish-cbc maps to on your end? I see they also have twofish128-cbc which would likely map to SSH_EA_TWOFISH128 (and perhaps SSH_EA_TWOFISH128_CTR) on the ELDOS side. However, what would twofish-cbc map to? SSH_EA_TWOFISH256?

Thanks.
#13582
Posted: 06/04/2010 10:10:38
by Eugene Mayevski (EldoS Corp.)

Twofish is not related to the problem in any way. Please post complete log.


Sincerely yours
Eugene Mayevski
#13585
Posted: 06/04/2010 16:19:34
by Scott Byam (Standard support level)
Joined: 05/28/2010
Posts: 9

Hi Eugene,

What is your email? I would prefer to email you the complete log file.

Thanks.
#13587
Posted: 06/04/2010 23:57:00
by Eugene Mayevski (EldoS Corp.)

Please post it to HelpDesk


Sincerely yours
Eugene Mayevski
Also by EldoS: CallbackFilter
A component to monitor and control disk activity, track file and directory operations (create, read, write, rename etc.), alter file data, encrypt files, create virtual files.

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