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SSH Tunnel hanging when transfering too much data

Feb 24 '16 at 11:56

I'm using ssh tunnel for getting data from a mysql-server via adodb. With the old library ChilkatSSh Version 9.4.1 all is running perfectly.

For testing I changed to ChilkatAx-9.5.0-win32.dll. Therefor I had to change some parts in the source: The new one needs an explicit lngSuccess = sshTunnel.Connect(strSshHostname, lngSshPort) and KeyFile-Authentification is done by lngSuccess = sshTunnel.AuthenticatePk(strSshLogin, sshKey)

The old one uses properties: sshTunnel.SshHostname = "" sshTunnel.SshPort = 22 sshTunnel.SshLogin = "username" and Authentification is done by lngSuccess = sshTunnel.SetSshAuthenticationKey(sshKey)

lngSuccess = sshTunnel.BeginAccepting(lngListenPort) (thats identical for both the new and the old lib) I connect the DB via adodb.

I have no differences in DB-handling-code, but the new lib hangs when the amount of data exceeds a level. Then I tested the tunnel with heidi, connection to the DB is no problem, I can retreive the table-list, but when the result of the query exceeds a certain level, heidi is hanging up. E.g. the query Select * From Articles Limit 100 is running fine, Select * From Articles Limit 1000 is hanging up.

The only difference is the lib I'm using.

Is it a bug?

Accepted Answer

Here's the new build that should fix it (finally)

32-bit Download:
64-bit Download:

If a build for a different programming language / operating system is needed, please let me know. Of course.. if any trouble is found, please let me know..


I'm investigating the problem...


PS> I can reproduce the problem and this is top priority. I will be fixed soon. (Once a problem is reproducible, it should be fixable..)

I'll post here once it's ready.


The problem is solved. I should be able to get builds together in the next 3 hours..


thanks, now it's running.

only for my knowledge: what was the cause of the problem?


I have been running into same problem with the .Net client. When 327680 bytes are transferred the connection hangs and sends no more. I am using the latest assembles from Dec 29th. Is it possible to get the fix for .Net 4.5, 4.5.1 and 4.5.2 as well?




This new build has the fix:

32-bit Download:
64-bit Download:

The problem had to do with internal SSH transport windows/flow-control..


Thank you very much. That was the solution.