Hi,

I am running WinSCP 4.2.7 and found it has difficulty with FTPES on busy Windows IIS 7.5 servers. When the server has a lot of http traffic, FTP without SSL is fast and reliable but FTPES repeatedly drops the connection:

. 2010-09-27 15:27:22.754 --------------------------------------------------------------------------
. 2010-09-27 15:27:22.754 WinSCP Version 4.2.7 (Build 758) (OS 6.1.7600)
. 2010-09-27 15:27:22.754 Login time: Monday, September 27, 2010 3:27:22 PM
. 2010-09-27 15:27:22.754 --------------------------------------------------------------------------
. 2010-09-27 15:27:22.754 Session name: ******
. 2010-09-27 15:27:22.754 Host name: ftp.H******.com (Port: 21)
. 2010-09-27 15:27:22.754 User name: H****** (Password: Yes, Key file: No)
. 2010-09-27 15:27:22.754 Tunnel: No
. 2010-09-27 15:27:22.754 Transfer Protocol: FTP
. 2010-09-27 15:27:22.754 Ping type: C, Ping interval: 30 sec; Timeout: 15 sec
. 2010-09-27 15:27:22.754 Proxy: none
. 2010-09-27 15:27:22.754 FTP: FTPS: Explicit TLS; Passive: Yes [Force IP: Yes]
. 2010-09-27 15:27:22.754 Local directory: C:\inetpub\wwwroot, Remote directory: home, Update: No, Cache: Yes
. 2010-09-27 15:27:22.754 Cache directory changes: Yes, Permanent: Yes
. 2010-09-27 15:27:22.754 DST mode: 1
. 2010-09-27 15:27:22.754 --------------------------------------------------------------------------
. 2010-09-27 16:25:24.235 Connecting to ftp.H******.com ...
. 2010-09-27 16:25:24.453 Connected with ftp.H******.com, negotiating SSL connection...
< 2010-09-27 16:25:24.687 220 Microsoft FTP Service
> 2010-09-27 16:25:24.687 AUTH TLS
< 2010-09-27 16:25:24.921 234 AUTH command ok. Expecting TLS Negotiation.
. 2010-09-27 16:25:25.405 SSL connection established. Waiting for welcome message...
> 2010-09-27 16:25:25.405 USER H******
< 2010-09-27 16:25:25.624 331 Password required for Hineynu.
> 2010-09-27 16:25:25.624 PASS *********
< 2010-09-27 16:25:25.858 230 User logged in.
> 2010-09-27 16:25:25.858 SYST
< 2010-09-27 16:25:26.092 215 Windows_NT
> 2010-09-27 16:25:26.092 FEAT
< 2010-09-27 16:25:26.591 211-Extended features supported:
< 2010-09-27 16:25:26.591 LANG EN*
< 2010-09-27 16:25:26.591 UTF8
< 2010-09-27 16:25:26.591 AUTH TLS;TLS-C;SSL;TLS-P;
< 2010-09-27 16:25:26.591 PBSZ
< 2010-09-27 16:25:26.591 PROT C;P;
< 2010-09-27 16:25:26.591 CCC
< 2010-09-27 16:25:26.591 HOST
< 2010-09-27 16:25:26.591 SIZE
< 2010-09-27 16:25:26.591 MDTM
< 2010-09-27 16:25:26.591 REST STREAM
< 2010-09-27 16:25:26.591 211 END
> 2010-09-27 16:25:26.591 OPTS UTF8 ON
< 2010-09-27 16:25:26.825 200 OPTS UTF8 command successful - UTF8 encoding now ON.
> 2010-09-27 16:25:26.825 PBSZ 0
< 2010-09-27 16:25:27.028 200 PBSZ command successful.
> 2010-09-27 16:25:27.028 PROT P
< 2010-09-27 16:25:27.246 200 PROT command successful.
. 2010-09-27 16:25:27.246 Connected
. 2010-09-27 16:25:27.246 Doing startup conversation with host.
. 2010-09-27 16:25:27.262 Changing directory to "/H*****/wwwroot/Logs".
. 2010-09-27 16:25:27.262 Synchronizing current directory "/H******/wwwroot/Logs".
> 2010-09-27 16:25:27.262 CWD /H******/wwwroot/Logs
< 2010-09-27 16:25:27.511 250 CWD command successful.
> 2010-09-27 16:25:27.511 CWD /H******/wwwroot/Logs
< 2010-09-27 16:25:27.745 250 CWD command successful.
. 2010-09-27 16:25:27.745 Getting current directory name.
> 2010-09-27 16:25:27.745 PWD
< 2010-09-27 16:25:27.979 257 "/H******/wwwroot/Logs" is current directory.
. 2010-09-27 16:25:27.979 Retrieving directory listing...
> 2010-09-27 16:25:27.979 TYPE A
< 2010-09-27 16:25:28.229 200 Type set to A.
> 2010-09-27 16:25:28.229 PASV
< 2010-09-27 16:25:28.478 227 Entering Passive Mode (208,101,42,67,162,182).
> 2010-09-27 16:25:28.478 LIST -a
< 2010-09-27 16:25:28.728 150 Opening ASCII mode data connection.
. 2010-09-27 16:25:29.258 SSL connection established
. 2010-09-27 16:25:49.482 Timeout detected.
. 2010-09-27 16:25:49.482 Could not retrieve directory listing
* 2010-09-27 16:25:49.529 (ESshFatal) Lost connection.
* 2010-09-27 16:25:49.529 Timeout detected.
* 2010-09-27 16:25:49.529 Could not retrieve directory listing
* 2010-09-27 16:25:49.529 Opening ASCII mode data connection.
* 2010-09-27 16:25:49.529 Error listing directory '/H******/wwwroot/Logs'.

After 15 or 20 times (each time "reconnecting" then repeating the above log) it will accumulate the full directory listing and list the directory so I could select a file to download/upload, then 1-2 minutes later the program will attempt to get an updated directory listing, starting the process again with another requiring another 15-20 timeouts. This is annoying (I've disabled viewing hidden files and still get the timeout errors), but I'm posting because when I attempt to download a file, the program attempts to do a directory listing again (even though winscp has the full path to the file) and the timeout errors never stop, the download freezes at 0% and never gets farther even after 30-45 minutes. This occurs whether downloading as a regular file or background download. It never issues the "RETR" command. When I attempt to manually enter the FTP commands in the FTP terminal:

$ TYPE A
200 Type set to A
$ PASV
227 Entering Passive Mode (208,101,42,67,162,213).
$ RETR [file name]
150 Opening ASCII mode data connection.
550 Data channel timed out.

Any suggestions?