Turns out WinSCP doesn't like when the FTP Server is configured to report external IP in PASV Mode.

Disabling this resolves my issue.

Further tests show it's the firewall on the destination FTP server. Just need to figure what needs adjusted...

I have a batch script that uses WinSCP to push new files to a remote directory over FTP. The files are around 80mb/ea and connections are 40/15mb fibre.

The script ran perfectly for over a year however now fails with error: Timeout detected. (data connection)

There is no change to configuration at the destination as far as I know. I can connect and transfer files as normal with FileZilla.

Can anyone suggest what the issue might be? Log sample and scripts below.


pushfiles.bat
--------------
set year=%DATE:~6,4%
set day=%DATE:~0,2%
set mnt=%DATE:~3,2%

IF %day% LSS 10 SET day=0%day:~1,1%
IF %mnt% LSS 10 SET mnt=0%mnt:~1,1%

set backuptime=%year%-%mnt%-%day%

C:\backups\winscp.exe /console /script=script.txt /log="C:\backups\logs\%backuptime%.log"

EXIT


script.txt
-----------

open ftp://username:password@ftp.domain.com
option transfer binary
put -neweronly C:\backups\*.* /mount/backups/
close
exit


log
----


2018-01-28 11:35:00.378 Connecting to ftp.domain.com...
. 2018-01-28 11:35:00.456 Connected with ftp.domain.com. Waiting for welcome message...
< 2018-01-28 11:35:00.472 220 Your FTP server ready.
> 2018-01-28 11:35:00.472 USER username
< 2018-01-28 11:35:00.503 331 Password required for username.
> 2018-01-28 11:35:00.503 PASS ********
< 2018-01-28 11:35:01.003 230 User usernme logged in.
> 2018-01-28 11:35:01.003 SYST
< 2018-01-28 11:35:01.081 215 UNIX Type: L8
> 2018-01-28 11:35:01.081 FEAT
< 2018-01-28 11:35:01.113 211- Extensions supported:
< 2018-01-28 11:35:01.113 AUTH TLS
< 2018-01-28 11:35:01.113 PBSZ
< 2018-01-28 11:35:01.113 PROT
< 2018-01-28 11:35:01.113 SIZE
< 2018-01-28 11:35:01.113 MDTM
< 2018-01-28 11:35:01.128 MFMT
< 2018-01-28 11:35:01.128 REST STREAM
< 2018-01-28 11:35:01.128 UTF8
< 2018-01-28 11:35:01.128 MLST type*;modify*;size*;UNIX.mode*;UNIX.owner*;UNIX.group*;
< 2018-01-28 11:35:01.144 MLSD
< 2018-01-28 11:35:01.144 211 End.
> 2018-01-28 11:35:01.144 OPTS UTF8 ON
< 2018-01-28 11:35:01.191 200 OK, UTF-8 enabled
< 2018-01-28 11:35:01.191 Script: Connected
. 2018-01-28 11:35:01.191 Connected
. 2018-01-28 11:35:01.191 Doing startup conversation with host.
< 2018-01-28 11:35:01.191 Script: Starting the session...
> 2018-01-28 11:35:01.191 PWD
< 2018-01-28 11:35:01.222 257 "/" is current directory.
. 2018-01-28 11:35:01.222 Changing directory to "/".
> 2018-01-28 11:35:01.222 CWD /
< 2018-01-28 11:35:01.253 250 CWD command successful.
. 2018-01-28 11:35:01.253 Getting current directory name.
> 2018-01-28 11:35:01.253 PWD
< 2018-01-28 11:35:01.285 257 "/" is current directory.
. 2018-01-28 11:35:01.285 Startup conversation with host finished.
< 2018-01-28 11:35:01.285 Script: Session started.
. 2018-01-28 11:35:01.285 File: 'C:\backups\2018-01-22-0200.zip' [2018-01-22T02:03:20.265Z] [90381212]
. 2018-01-28 11:35:01.285 Copying "C:\backups\2018-01-22-0200.zip" to remote directory started.
. 2018-01-28 11:35:01.285 Binary transfer mode selected.
. 2018-01-28 11:35:01.285 Starting upload of C:\backups\2018-01-22-0200.zip
> 2018-01-28 11:35:01.285 CWD /primary/backups/mysql-dumps-ds/
< 2018-01-28 11:35:01.378 250 CWD command successful.
> 2018-01-28 11:35:01.378 PWD
< 2018-01-28 11:35:01.409 257 "/mount/backups" is current directory.
> 2018-01-28 11:35:01.409 TYPE A
< 2018-01-28 11:35:01.456 200 Type set to A.
> 2018-01-28 11:35:01.456 PASV
< 2018-01-28 11:35:01.488 227 Entering Passive Mode (217,155,46,234,253,218)
> 2018-01-28 11:35:01.488 MLSD
. 2018-01-28 11:35:16.160 Timeout detected. (data connection)
. 2018-01-28 11:35:16.160 Copying files to remote side failed.
. 2018-01-28 11:35:16.160 Connection was lost, asking what to do.
. 2018-01-28 11:35:16.160 Asking user:
. 2018-01-28 11:35:16.160 Lost connection. ("Timeout detected. (data connection)","Copying files to remote side failed.")
< 2018-01-28 11:35:16.160 Script: Lost connection.
< 2018-01-28 11:35:16.160 Script: Timeout detected. (data connection)

< 2018-01-28 11:35:16.160 Copying files to remote side failed.