wodFtpDLX.Net: slow connection and timeouts - WeOnlyDo Discussion board

wodFtpDLX.Net: slow connection and timeouts (wodFtpDLX / wodFtpDLX.NET)

by dfb, Tuesday, April 07, 2020, 10:04 (167 days ago)

Hi all,

We use wodFtpDLX for a number of connections without problems, but recently noticed an issue with certain servers.

The remote SFTP server in question is using Tectia SFTP - their server reports this version at logon: "Server version: SSH-2.0-6.4.14.26 SSH Tectia Server"

Our connections work fine using wodFtpDLX 1.8.4.248 on Windows 2012 R2. Connect/push file/rename file/disconnect in about 1 second.

However running the same software on Windows 2019 we get long delays during connection and when pushing and renaming files. This can easily take 60 seconds per step, but sometimes even longer and we get a timeout.

We have seen the same behaviour with wodFtpDLX 1.9.0 on Win2019.

Has anybody else seen this type of issue?

Thanks.

wodFtpDLX.Net: slow connection and timeouts

by Jasmine, Tuesday, April 07, 2020, 11:03 (167 days ago) @ dfb

Hi.

When do you see delays, do they happen sometimes with that server, or each time? If you try this server against our sample code apps, does same thing happen?

Jasmine

wodFtpDLX.Net: slow connection and timeouts

by dfb, Wednesday, April 08, 2020, 01:17 (166 days ago) @ Jasmine

Hi Jasmine, thanks for the response.

We see slow connections and/or timeouts consistently when connecting from Win2019 to that specific server.

We don't see it when connecting to other servers from Win2019, and we also don't see it when connecting to that server from Win2012 R2.

We've been using a test harness based on our own code, but I'll try it with your sample code - thanks!

wodFtpDLX.Net: slow connection and timeouts

by dfb, Wednesday, April 08, 2020, 08:26 (166 days ago) @ dfb

Just to verify, seeing the same results with the VB.Net sample code (modified only to set licence key and to specify Protocol as SFTP).

Thanks.

We've been using a test harness based on our own code, but I'll try it with your sample code - thanks!

wodFtpDLX.Net: slow connection and timeouts

by Jasmine, Wednesday, April 08, 2020, 10:18 (166 days ago) @ dfb

Hi.

Ok, in order to isolate this issue I'd like you to check if connection is idle for that amount of time, or simply transfers are slow. I assume you perform a file transfer when this happens. If you check Progress event, does it fire and does it actually transfer files, or everything just stops?

Any chance we could connect to that server for a test?

Regards,
Jasmine.

wodFtpDLX.Net: slow connection and timeouts

by dfb, Thursday, April 09, 2020, 04:02 (165 days ago) @ Jasmine
edited by dfb, Thursday, April 09, 2020, 04:09

Hi Jasmine,

If we use events (blocking mode off) then we don't see the Connected, Done or Progress events fire.

Our network guys said the remote server is sending many retransmissions of the same packets during the connection and later stages (on the rare occasions it connects).

Unfortunately it's not our server, so we can't give you access to it, though I will ask them. Not sure if it's possible to get a trial of the Tectia SFTP server software to try it. https://info.ssh.com/tectia-ssh-server-trial-download

Thanks

wodFtpDLX.Net: slow connection and timeouts

by Jasmine, Thursday, April 09, 2020, 14:43 (165 days ago) @ dfb

Hi.

If you see many re-transmissions, then this sounds like socket issue, not application issue. Do you have any other connections (not SSH or SFTP) to that server, how does that work?

From application's perspective, we can't even interefere with raw (TCP) packets, we can simply Connect, Send, Receive, Disconnect.

Jasmine.

wodFtpDLX.Net: slow connection and timeouts

by dfb, Wednesday, April 15, 2020, 08:25 (159 days ago) @ Jasmine

Thanks.

We have tried connecting using other SFTP clients such as psftp

That is successful, so it appears to me to be a combination of SFTP client running wodFtpDLX on Win2019 Server + Tectia SFTP server

We'll keep digging, but any other suggestions very welcome!